Let's assume a man is following little children (not against the law, nor a sex crime). He is questioned by a police psychologist, to whom he tells that he wants to rape children. What's your game plan?
The man is clearly a danger to children and society in general.
What a lot of people offer as a cure for the problem is easily 1 million times more dangerous than letting the man go.
For example, I just recently found out that SCOTUS overruled a KS decision that found that sexual predators could not be identified after being released. In other words, SCOTUS decided that even though the men had served their entire sentence, the court could arbitrarily extend that sentence on the simple word of a psychologist. It seems similar to the situation decribed in this thread, this one just hasn't been overturned by SCOTUS yet. Hopefully, we will have another Constitutional member on the Court before it gets there.
These are truly situations where the phrase 'the cure is worse than the disease' fits perfectly. One only has to look at the Russian Gulags to see what direction this is headed. Millions of very brave, very loved, young AMericans have died to protect us from this. I hope their deaths weren't in vain.