I have never been a sexual predator and will commit to never being one in the future. This is something I would wager the vast, vast majority of the public can commit to too. This is not something weird or out of the ordinary.
To quote Cardinal Richelieu, "If you give me six lines written by the hand of the most honest of men, I will find something in them which will hang him."
This behavior really has nothing to do with the nature of the crime at hand; it's been used to discriminate against people by race, by gender, by interest, by religion - by just about anything. Giving human beings the ability to arbitrarily punish other humans, without recourse, is obscenely dangerous.