1. They do.
2. Many of these sites are for sharing kiddie porn. You know like Reddit, YouTube, and Blogs are for sharing things. The consumers are often the creators.
3. " It's rather like penalizing people who drink poisoned water rather than finding the poisoners." Really? These people are going to a tor dark web site called the playpen and you are trying to paint them as victims? How about this instead, "it is like penalizing people that pay people to sexually abuse children for there entertainment".... Yea I got no problem with this.