imagine if you are trying to collect evidence for a murder trial but its illegal to give testimony about violent crimes so if someone tries to tell you they saw the guy shoot the lady they put the witness in jail for talking about violent crimes.
the child stuff is mostly just a surveilance vector / getting to yes backdoor. the state doesn't do shit when there's an actual child exploitation ring and they go after everyone who tries to stop them.
in order to even make hashes someone has to have had it in the first place. how can you confirm the hash is properly guilty if you can't source it? how can you confirm the hash is a valid match if you can't verify it? does some priesthood just divine numbers and hand them out? this is not a policy designed by someone trying to genuinely solve the problem.
