It's really interesting to me, this. I'm old enough to remember the last system that was really impossible to censor. It was called #Usenet, though some called it #NewsGroups.

Exactly the same thing happened. One they realised it couldn't be censored, they started spamming it. Usenet came up with a solution. I hope #nostr does too.

I'll end by checking you realise this can be filtered very effectively at the client level byt muting the user. This user always has reply in his nick.