I think you're transferring a fedi position to nostr.

The button being discussed wouldn't block a specific fedi instance, it would block the entirety of activitypub from nostr. I could actually see the utility in being able to filter at instance level i.e. pulling the sequence between the _ and the @ to block your instance mastodon.nzoss.nz but once again even then, while better than blocking the bridge we are still transferring one of the worst parts of fedi to nostr.

If you've ever seen a real dogpile you would know the most mentally ill people will happily create 27 different accounts on different open servers to attack their targets. If people want to attack a nostr user they're going to be able to create unlimited npubs directly on here for that purpose, it's literally even easier than what they do now on fedi.