I don't really think Nostr is actually any better for this. Because an upload on Blossom is equally vulnerable to copyright complaints. I don't think Blossom operators are going to ignore properly delivered and formatted DMCA requests and expose themselves to liability. The only reason they haven't really been targeted is that not a lot of people are using Nostr.

What really is "copyright" in the AI world? dust in the wind...

that's a nice sentiment but if you ignore it in most countries people will come with lawyers to take all your property