What you are talking about is the user choice to use alternative tools/services and that is and important part but we have not seen any real attack on nostr yet.

If nostr.build would be taken down we would loose a lot of existing content in nostr. We could move on and recover by using a different service but it would be huge impact.

Ultimately app store bans, domain name takedowns or cease and decist orders against domain holders could be used to "censor" the network.

I'm not sure if it's good that we rely on the usual cloud providers and domain names so much, or if we should at least have decentralized P2P solutions as a backup.