Well, God does. And He condemns it for the sin it is.
It might be unwise or even self-destructive, but in a free country such as ours, we do own our lives and bodies, after all.
No man is an island.
Now, if I thought it were all right in one situation, but not in another; or for one person or group, but not for another - that would imply I was a moral relativist.
But you are because you just qualified the behavior in the previous paragraph as *private*. That implies that you think that *public* , non-violent, sexual behavior IS immoral. That would make it moral in certain circumstances and immoral in others.
Yup, that's moral relativism.
Passe John Donne, all men are islands. We just live in an archipelago and have a right to our own boundaries, even while we share common and voluntary bridges as a means to commerce and free exchange of value. Yet, civil society depends on commonly-accepted rules of behavior and when some seek to offend as a means of altering those rules, they ought to lose their rights of passage.
I don't know if you remember, but one of the early catch-phrases of the so-called "gay rights" movement was "Out of the bedrooms and into the streets!" I think that is when they gave away their intention as political power, not personal liberty.