The only reason you could say the state has no legitimate authority to do so is that there is a protected constitutional right to engage in that kind of behavior. If that is the case, you would have to agree that a person has a constitutional right to engage in bestiality and necrophilia. If you are willing to let the country to go in that direction in order to maintain some libertarian idea of freedom, you need to have your brain examined.
Since you appear to defend the unfettered right to be a pervert... No I won't go there. Please do not tell me that my daddy almost lost his life in Korea so that now I have to justify the action of government to restrain the acts of perverts.
Excuse me. I think I will end my discussion on this thread. The filth embedded in this libertarian mindset makes me want to puke.
Your daddy didn't go to Korea to restrain perverts. He went to Korea to keep you free, which you, in turn, so ungraciously deny to others. I'm betting the reason he went there to keep you free was so you could stand up on your own two feet and think like a rational man, instead of being ruled by your fears like an animal. I'm guessing he's pretty disappointed.