At least, in public, homosexual apologists bitterly resent comparisons between homosexuality and bestiality. Today I ran across this discussion of Reddit:
Within the swampier quarters of the site, you will find all sorts of insalubrious offerings. One area features graphic discussions of bestiality.
I haven't read the Reddit discussions of bestiality, and I don't intend to. But the immediate point is that this isn't just hypothetical. It's one of current alternative sexual activities. Not a bogeyman that rightwing Christians fabricated to create invidious comparisons with homosexuality.