The protection of children is the task of their parents imo.
Maybe I misunderstood, but nostr:npub1aeh2zw4elewy5682lxc6xnlqzjnxksq303gwu2npfaxd49vmde6qcq4nwx removed mostr relay in his client only for himself and did not propose to completely cut off (for example) the fediverse from Nostr...
And I’m not rooting for centralized subjective censorship, but imo everyone decides for themselves what content they want to see and what to afraid of. For example, I don’t read global feed at all. And mute every npub I don't like.
But how to protect children from shocking content and whether this should be done is a more important question.
Discussion
You're talking about mainstream adoption. With growing adoption will come attention from governments. Children are an active internet users. Theoretically they might be interested in Nostr, for example, in the donation mechanism. Laws are protecting children. Nostr community can't ignore the problem of shocking content just because it's parents' task. Because it's government's task too. At least parents expect the state to do this. Eventually relays will be blocked in developed tolerance-oriented countries and no mass adoption on the board anymore.
#Nostr is a protocol and does not care about. You have to choose if you want freedom or censorship, it's your choice ✌️
You, not me talking about mass adoption. Fediverse is not a mix of mass adopted protocols and apps. They chose freedom. I'm just speculating what this might entail if Nostr grow big...