Libertarian is not left on social issues

[Dystopia]

Why not?

Because it is an important social institution that people value and grants certain privileges and stability to raise children (the next generation)? There's many reasons to ban marriage, and many reasons to not do it - Ultimately, if people want to get married the State shouldn't stop it from happening.

Given that reproduction is a deep-seated biological urge, do you think this is really a necessity?

Is it? But doesn't the number of children you have depend on many variables? If so, why is it that my country has a lack of young people and if it wasn't for immigrants we wouldn't have a significant young workforce (Europe has these problems)? Of course it is a necessity as the demographics and age of the population interact with employment rates, inflation, etc, and the State has the duty to run society the best possible way to make us all minimally satisfied.

Is it the government's place to manage family size?

What do you think of China's "one child" policy?  

Would you accept enforced abortion?  Or enforced impregnation?

First things first - Would never accept forcing anyone to do anything - But that doesn't mean the government can't pursue policies depending on the demographics - Again, using the example of Portugal, we have too many old people because back in the day people had 7-8 kids and some had 30 kids (seriously my mom knew an old lady who had literally 33 kids) and now with the emancipation of women and unemployment, etc, we have fewer young people - What should my government do? Just stand there and not give two shits? Economic planning isn't just about promoting and funding private enterprise to boost profits and the GDP, it's also about playing with other variables and knowing how to predict issues in the future that will arise if you don't do anything about it.

This does not mean I support extremist measures like forcing people to have X or Y kids, but it is possible to take some minimal measures to boost some variable you'd like to see growing - I don't see anything wrong about it - Not to mention that the benefits you have in taxes with kids exist for other reasons such as the fact married people spend a lot more of their income with children duties like diapers and food - It seems fair to me.

Marriage is indeed a contract. The question is, is that contract actually necessary for human beings to tie life to life? Power-of-attorney agreements can manage every benefit marriage gives but taxes (in some cases).

In my country, there are benefits marriage gives you that you can't get with any other contract. For example, if you are married to someone and they just die, you have a right to 50% of their belongings (Unless you have kids because then it's only 30-33%) even if they didn't sign a testimony saying so, but if you're not married to them you need to sign a contract before otherwise you won't get that percentage of belongings. Obviously there's other legal benefits like matrimonial regimes that allow a different and more pragmatic management of your personal goods and belongings that you can't get without a marriage contract. 

Just because a thing is subject to regulation doesn't mean that it should be subject to regulation.

Indeed, but sometimes it should - Specially life-changing super important contracts like marriage and even employment contracts. I don't know what you think, but IMO the most important contracts people ever sign are matrimony and employment (long-time) contracts - Those contracts shape your life and allow you to fulfil your most important desires - Because these contracts are so important and it would be a shame if someone used the law to abuse, twist and hurt others trough those contracts, there's a need for the government to regulate. That's why my country has a law saying husbands and wives are equal to prevent old school patriarchs from doing their thing - There's also laws saying a minimum salary must exist to prevent extreme poverty or saying you can't fire someone because of their race without paying them a compensation in money.

Punishing someone for their viewpoint is profoundly antidemocratic; requiring them to remain silent on said views is in itself a punishment. What if the restriction on speech was -- instead of racial hatred, which is I gather your point -- what if it restricted your ability to speak out on your atheism?  Because that too is offensive to many people (rightly or wrongly).

A free country has many freedoms, but one does not have the right to be free of offense. And rather than prosecute speakers who urge violence, as Tiberius notes, 'tis better to prosecute the violent themselves.  After all, they made the decision to act on the words. 

 Silencing hateful views doesn't lead to eliminating those views, it leads to driving them underground where they can grow and fester. Both in the abstract and pragmatic spheres, hate-speech laws are counterproductive.

I think I should reformulate my position - Only when someone does something like Adolf Hitler should they be arrested because they are effectively endangering public sphere and possibly causing riots and violence - I don't think your opinion should be a crime, or hate, I think inciting something that already is a crime should be illegal. Now, I certainly don't think inciting hate per se should be illegal, but if someone incites hate and then the result is other people doing harm to others because of the hater, this person should be punished because they basically act as one of the main sources of the crime's motives. I mean, if I told you to kill someone of your family for money and incited you to do it infinitely, shouldn't I be punished in court if you end up doing it (Of course you would be punished as well)?