In the first case there is no mutual consent, in the second there are severe biological reasons
Them's the short answers.
The perception of morality does enter into it too.
I find those morally offensive. While I find homosexuality physically repulsive I have no moral objection to it.
And it is of course possible to have moral objections to anything without being bigoted.
Bigotry depends on actions, words and intent, not objection....
