"- A law like this would not be easily enforceable."

Encryption and a proxy would mean law enforcement could not check the person's computer from that end or where they have been going from the isps end. Both of which can be done easily and for free so yes. Only for sure way is to keep RSOs from using the internet which I could see happening. That would not be easy to enforce but a little easier.

"- As one of the comments pointed out, what about sites/forums specifically dedicated to supporting sex offenders? Are those prohibited, too?"

I have not read the actual bill so I don't know for sure but I would not think so. If the bill is not very specific it would have to be tested in the court of law to see how a judge interrupts the law. Hopefully the first person caught in that trap fights it and wins so it does not set a precedent for the opposite.

"just setting him up for seeking some form of interaction elsewhere."

Some of them think these laws are for prevention and some of them know it is about punishment and has nothing to do with prevention. Clearly making it harder and harder for RSOs to find a place to live, work, and positive social interaction leads to way more people re offending rather than preventing it. This is about punishment for exactly the reason you mention next.

There is no justice in that. Many people in the United States of Americka have a much bigger problem with sex and nudity than death and violence. Little Johnny is supposedly more traumatized by seeing some butt on tv than death and some people have said death is better for them than molestation because you have destroyed their soul.