I don't know what percentage of people using Tor for illegal activity would be incautious enough to run some random program on their computer, but I would be surprised if it was very high.
I think it would certainly depend on the type of "illegal activity"; it's quite plausible that those looking for drugs or counterfeiting are going to have much higher suspicion and opsec than porn-driven pedophiles, leading to the difference in number of registrations at each honeypot.
Another thing is that Tor is global. People might not think twice about their security when they are effectively within the law or at worst may get a fine.
I think it would certainly depend on the type of "illegal activity"; it's quite plausible that those looking for drugs or counterfeiting are going to have much higher suspicion and opsec than porn-driven pedophiles, leading to the difference in number of registrations at each honeypot.