Do we know better? Those things can definitely be sin, depending on what is going on in the minds of the people doing it.And if God was concerned about two people having skin contact even greeting others with the customary kiss or handshake would be sinful. But we do know better than to make that a sin.
That's the problem with unbelievers. They're dumb. The fool in his heart has said there is no God. They don't need the answer to this question- it won't help them if they don't believe in God already. Cleaning the inside of the cup first and what-not.Why would God say that sex outside the bounds of marriage is a sin? That is the question for today amongst the unbelieving population.
Doing any sin without repentance will harden the heart. Hopefully you mean "a callousness that is impossible to recover from-without Jesus-).A prostitute has words dripping with honey. But engaging in physical intimacy with a prostitute hardens your heart about physical intimacy. Creating a callousness that is impossible to recover from. Lust is a never satisfied beast...and orgasms don't fulfill the desire.
Love and acceptance fullfil the desire for sex...not just the act of sex with someone who is making a business transaction.
Orgasms do fulfill sexual desire- but what they do not fulfill is the low self-esteem and loneliness caused by the spiritual void they are trying to fill with their fornication. (it doesn't have to be fornication either- some sin that stimulates the emotions, or overloads the nervous system in a way that numbs the pain caused by the spiritual void. Drugs do the same thing.
Love and acceptance fulfill the desire for love and acceptance. You can get that at church- what you cannot get at church is sexual fulfillment- you can get that from your spouse... but hopefully not while you're at church. Get a room.
People that draw doctrinal lines are doing the right thing. It's what the epistles say to do. There's plenty of "Christians" worshipping a very different God, following a very different Jesus than me. While I won't de-humanize those people in any way, I'd definitely not fellowship with them if they're teaching the doctrines of men. That's the way it is.Baptists encouraging their fellow denominational brothers and sisters to view the Methodist as something less than Christian and enemies of the Gospel. Those Baptists who engage in encouraging others to view them as such are prostitutes....
Drawing political lines is similar. Politics decides who makes the law for a nation. The law is derived from doctrines. In the same way I wouldn't want my family learning false spiritual doctrine from a false teacher, I wouldn't want my nation misled about what is right and wrong in the Law either. When a politician wants to say there is nothing wrong with (we will use your example) prostitution and that it should be legalized... that politician and his supporters speak for Satan. Because that's what they're doing. We don't de-humanize people... but we can't let sensitivity to their feelings compromise our integrity.