Similar considerations are why I never ran a Tor exit node, despite my inner geek wanting to as soon as I heard about it because the technology is cool.
The deciding factor was that almost every good thing that I could think of or that people suggested that a truly anonymous, untraceable, non-moderated, anybody to anybody communication system could be used for were things that could be reasonably accomplished by other means that are not as open to abuse.
For example, a common scenario offered is someone inside an oppressive regime working to document the regime's abuses and bring it down. They would be tortured and killed (and possibly so would their family) if their identity became known.
But they just need a need a secure channel to a trusted contact outside the reach of the regime who can relay messages for them. It does not have to be an anybody to anybody channel or a non-moderated channel.
The only things I could think of that really need something like Tor are things where what you are doing is so near universally frowned upon that there is almost nobody willing to be publicly associated with facilitating it.
Probably will get scooped up by pedophiles sooner or later, followed by a couple high profile arrests and everyone will be scared shitless to run a node for that blockchain. CP has always been a good source of scare for Tor exit node operators, thankfully enough Tor nodes don't store the stuff in contrast to a blockchain - so at least the operators didn't have to serve jail time but a couple have had their houses raided by the cops and all IT equipment confiscated for months.
Actually, from a libertarian POV I really like the idea, both behind an uncensorable imageboard and Tor, but the simple fact that pedophiles and Nazis can and will abuse the openness for their vile gains makes me believe that the world will probably never be ready for such a thing as widespread service. For now we as society have to be lucky that many pedophiles, drug dealers and Nazis don't really care about good opsec... but that one is bound to change.