Feminism was retrofitted into libertarian theory, to fill the gaps in its coverage
Wouldn't it be accurate to say that libertarian theory is fairly weak and incomplete in the area of family law?
There are a lot of areas where libertarian theory is stronger. For example, they've had a lot to say about drug legalization. They've even created whole organizations devoted solely to that one issue. They've had a lot to say about economic issues like the minimum wage or price ceilings. They've even written about privatization of highways and other roads.
But family law? Not so much. And it seems to me, when libertarian theory is weak in an area, what they do by default is import theory from other ideologies (especially mainstream ideologies that have gained widespread acceptance) to fill in the gaps, even when those other ideologies aren't libertarian.
Rothbard didn't have a lot to say about family law, other than saying that blacks wouldn't be so poor if they would finish their education rather than having a bunch of kids outside of wedlock. Marriage was assumed to be part of the solution, but libertarian theory hasn't said much about how to defend marriage from threats like divorce.
Even marriage equality (i.e. gay marriage) seems to me like doctrine imported into libertarianism without much thought as to whether the idea was really all that libertarian. Like most of the public, Libertarians tended to hail the Supreme Court decisions legalizing gay marriage everywhere as a great victory, and even said, "We were for marriage equality all along, since the party's formation in 1971."
But what does gay marriage really amount to? It means, for example, that now, companies will be forced to provide insurance coverage to their employees' same-sex spouses. Libertarians might argue, "We don't support forcing them to do that." But if not, then what was the point of legalizing gay marriage? When civil unions existed, gay couples still had the benefits of having a binding contract between them, but the state didn't force people to recognize their relationship.
Most of libertarian theory pertaining to minors has also been imported from other ideologies. I'm not aware of libertarians having a theory about what should happen when a couple splits up and the kid needs to go with one parent or the other, for instance. I'm not aware of them having a theory about what should happen when the state thinks that a parent poses a risk to their own child, based on the parent's statements (rather than actions).
So by default, I guess they yield to the feminists on those issues. How could they do anything else? They don't have a theory that would equip them to say, "No, feminists, your policy is wrong. Let me explain the libertarian principles that apply to this kind of situation, and what we would propose doing instead."
If we're going to import a possibly anti-libertarian theory into libertarianism, though, why should it be feminist theory, rather than, say, red pill theory? What's the benefit of giving women supremacy over men, rather than men supremacy over women? If one wants to argue that neither sex should have supremacy, then I say to libertarians, go ahead and come up with your own theory of how that should work, and explain how it would apply to the various situations that may arise in family law.
Till you've done that, you leave people who have an interest in family law no choice but to advocate possibly unlibertarian proposals, just to fill in the gaps. It would be like if libertarian theory had nothing to say about drug policy. People who care about drug policy would probably be standing around arguing about whether treatment or incarceration is superior, when the libertarian answer is just to legalize drugs altogether.
The ages of consent and marriageability
The LP's stance on the ages of consent and marriageability (which are not officially spelled out in the platform, because they would never want to draw attention to that issue, or get into the debate needed to add it, but they might claim it's implied) was also imported from feminism.
First of all, the question of under what circumstances sex with a kid can cause harm to that kid is an empirical question. Complicating this is the fact that different kids may respond differently to sex, just as different kids may respond differently to, say, schooling.
Libertarians are in general agreement that adults have to make decisions for very young children (e.g. infants), and they also agree that parents don't have a right to commit aggression against their own children. (On the issue of neglect, there's a split between anarcho-capitalists, who say neglect is okay, and more moderate libertarians, who say that it isn't.)
Anyway -- what counts as parental aggression against a child? Here, again, there's some disagreement. Some libertarians say spanking is okay, and others say it isn't. But spanking is sort of like vaccination, or making your kid eat vegetables that he would prefer to refuse. The idea is that you're forcibly causing some temporary pain for the child's own good, and/or for the protection of those around him.
If spanking helps the kid develop discipline and deters him from infringing others' rights (e.g. if it keeps him from violating his parent's property rights by stealing all the cookies from the cookie jar), then arguably it's okay. All the alternatives, such as putting him in time-out, would have involved some other use of force anyway. The question of whether spanking causes long-term psychological harm to the kid is an empirical question, which there have been some studies about, but of course, studies can be flawed.
So then, what about having sex with kids? Most libertarians, importing their views on the matter from feminism, would say that it's okay for a kid to have sex with another kid, but not for an adult to have sex with a kid, because that's "exploitation" or "abuse."
Any time you hear a libertarian say "exploitation," you pretty much know he just imported an idea from either feminism or socialism. We might say the same about "abuse," which is not a libertarian term either. Libertarians talk about "aggression" because it's a more precise concept that's specifically tailored to the concerns of libertarianism.
"Exploitation" focuses on imbalances in economic and social power that make one party more inclined to give in to the demands of another, even if it's not because of force or fraud. Libertarianism therefore usually doesn't care about exploitation, since their ethical system doesn't
"Abuse" is a more nebulous term than aggression, basically meaning anything that you do that causes another person emotional harm. Abuse, then, could include, for example, verbal abuse, emotional abuse, etc. which are very large categories of behavior having nothing to do with aggression.
So then, what kinds of decisions fall under parental discretion? There has to be some discretion for the parent to decide how to raise his young kids, especially when the evidence about best practices is unclear.
There has to be some parental discretion in order to accommodate the unique needs of individual families, and so that families can be laboratories for experimental parenting ideas.
The question about whether sex between adults and kids harms kids is an empirical question. If the evidence is unclear about whether it does, then that's a matter that falls under parental discretion, just like vaccination (and, perhaps, like spanking and circumcision). Parents who make poor decisions in their use of discretion will be punished by evolution.
Libertarians haven't had much debate about the ages of consent and marriageability, because feminists have stifled and suppressed that debate. People like me who openly dissent from the feminist party line are purged.
But, let's look at the question of child rape. If you can force your kid to accept vaccination, or vegetables, or schooling, or playing outside when he'd rather sit around playing video games, then why not force him or her to have sex as well, if you think it's for the kid's own good? For example, one might say, "Sex will help benefit our relationship; it will be good bonding time."
One might argue, "Sex that's forced is unlikely to be of benefit to the person who's being forced." Why would sex be different than the other stuff that is forced on kids? Often when kids are forced to do stuff, they try to make the best of the situation, and may even later say they're glad they were forced. For example, a kid forced to read a book may later quote from that book and express gratitude that it was required reading, and perhaps require his kids to read it too.
Women sometimes describe how, after they were initially reluctant to have sex, finally, after their husband continued trying to initiate sex, they acquiesced, and then became aroused and enjoyed it. Why wouldn't it work the same way with child rape sometimes?
Of course, we don't hear kids saying, "I'm glad I was forced to have sex," because as we saw with Milo Yiannopoulos, that's very politically incorrect and will get you kicked out of movements and organizations.
Sometimes the stuff that is forced on kids isn't even mostly for the kid's own benefit, but is for the benefit of the family. For example, a kid may be forced to walk the dog or take out the trash. Why should the kid's interests have primacy over the interests of the family? If I, the parent, want sex from my kid, why should the kid get her way, and not me, assuming there's no clear evidence that such rape would be any more harmful than ordering a kid to do chores?
Why should I be kicked out of political movements just for asking such questions and putting forth an idea for others to refute if they can? Why is such advocacy less tolerated in the libertarian movement than advocating other kinds of ideas that some libertarians feel is incompatible with libertarianism (for example, a carbon fee, a vehicle miles driven tax, a burqa ban, etc.)? Why is a pro-child rape faction not allowed to emerge in the libertarian movement, but other kinds of factions that deviate from libertarian orthodoxy (e.g. geolibertarianism, left-libertarianism, etc.) are allowed?