I use it not to share pictures nor commit crimes but to do what you say is worse: talk to other pedophiles. Tor permits us a safe support forum.
fatbird says: Whether or not they exist anyway, it seems obvious to me that a supportive peer group is going to increase their effectiveness at predation.
Quite the opposite in fact. Dialogue among pedophiles facilitates two things that you might not have expected:
1. Greater awareness of the draconian consequences which generally result from breaking certain laws, and a corresponding discouragement of doing so in the first place.
2. Most importantly, it gives us role models beyond the ugly stereotypes society has created for us: each other. Since role models are by definition templates for action, this makes it far less likely that we'll act as badly as society would expect.
I can't claim that all pedophile forums are like this. But the ones I frequent -- which are among the most popular -- are, and the less we're driven underground, the more our dialogue will resemble my description and the less it will resemble yours.