It is if all you're doing is trying to spam, you just need throw-away accounts for that.
Discussion
yep so this has been done, bots that generate a new npub key for every post, nostr:npub1xtscya34g58tk0z605fvr788k263gsu6cy9x0mhnm87echrgufzsevkk5s shortly introduced ip bans at his relay and we could also make proof of work needed on npubs at relays or posts
nostr works, due to nostr:npub180cvv07tjdrrgpa0j7j7tmnyl2yr6yr7l8j4s3evf6u64th6gkwsyjh6w6 's common sense nostr has choosen a path that works and subsequent devs have done similar, any problems that arise will have solutions