I’ve had to deal with a situation once where a user received spam containing links to CP via a major IRC network. Weeks of paperwork and trouble, caused by a few seconds of work for the spammer. Spammers abuse this imbalance of work to easily take down services, many of which won’t ever come back online (I certainly won’t ever host free IRC bouncers again, it’s definitely not worth it).
This is what truly destroyed the open, federated web: humans being disgusting animals.
CP is a very touchy subject. But if we really wanted to solve the problem we shouldn't focus on someone accidentally seeing (and thus caching) CP on their device.
CP should be removed at the source, by doing everything we can to take care of kids and preventing abuse and related photography. And CP trading rings should be busted.
But individual pedophiles should be helped with their mental health issues before they act and become pederasts. The subject is so toxic that nobody dares go to a therapist with their issues. There was a recent documentary about it: https://www.idfa.nl/en/film/bb3cd43c-169a-48db-9fd6-e4cbae0d...
Coming back to crypto. Who cares if the images are shared using crypto or on paper or on usb sticks? Once you find a pederast, law enforcement should convince (without torture or similar tricks, offering therapy and help will probably be more effective) them to help expose their network. Same with any activity that is using encrypted communications: https://edri.org/files/encryption/workarounds_edriposition_2...
You can take screenshots of encrypted content and the whole aspect of encryption is basically defeated if the channel itself is open to the public. This might not have been the case here, but there are people that infiltrate channels like this on purpose to report them to authorities and Google(?).