This is how queer theory ended up endorsing paedophilia. If you can’t define sex, then you can’t define consensual sex. And consent ends up going out the window.

Bestiality and paedophilia are wrong because it is people in positions of greater power (ie adults) imposing their will on somebody who can’t consent to the act. Sometimes it’s okay to make children and animals do what they don’t want: eat their greens, have a bath etc because you are doing these things both for the child or animal’s good and for wider societal benefit. Having sex with children or animals is not done for the benefit for anybody but the adult human doing the thing.

Also incest taboo due to possibility of offspring born with birth defects. HORRIFYING BIRTH DEFECTS.