Wow, so many questions in so little space. Is this leading somewhere?
To answer: The person engaging in the "unnatural acts" is doing so by choice. He may be harming himself. He has a right to harm himself. God obviously intended that he have that capability. else he'd have been created without free will. The right to harm himself comes from his self-evident nature as a free being. He can't violate his own rights. (Should he sue himself?) The things he does to himself may "hurt" others who want something from him. Your contention that he harms or diminishes "society" is just that, a contention. I'm not buying. "Society" is an abstract - the individual we're discussing, while hypothetical, is real.
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God obviously intended that he have that capability.
Man has the capability to do many evil things. Does that mean that he has a right to do evil things? I don't think that defense will hold up on the judgement day.