We're talking about convicted sex offenders, so the fact that they've committed a crime is a given. And I don't think anyone in this thread is even remotely suggesting that sex crimes shouldn't be considered crimes.

But we don't allow victims of crimes to mete out "justice" in America. We try to deliver justice in an impartial way, and a way that's fair to everyone and protects everyone's basic civil and human rights. (We don't always succeed, but that's what we aspire to.)

And we don't consider "an eye for an eye" justice, either. A monstrous act doesn't mean that we institutionalize monstrosity by behaving in kind. If you want to be ethically consistent, you can't punish someone who uses their body to invade someone else's by using the power of the state to violate the offender's body!

We also have to be careful that the sentences we impose don't degrade or harm the people who have to carry them out.

And even sex offenders have rights: preserving civil and human rights for those who maybe least deserve them helps insure that that we ALL keep our civil and human rights. (It's kind of like that 1st Amendment mantra paraphrasing Voltaire: "I may not like what you say, but I'll fight to the death for your right to say it.")