damus blurs photos from non-friends default, so you wouldn't even see these unless you

a. connected to the weird japanese relay b. followed people who were posting this stuff

Also nostr doesn't store media unlike mastodon instances, so clients could block image hosts serving this stuff.

having been online for almost two decades and never having seen childporn, the gatekeepers have done well. I have been inadvertantly subjected to all other kinds of content. Drugs, homo sexual porn, animal porn, violence, racism, libartarianism but no child porn. so good job, i guess.