nostr:npub1gajvsj4vhehzjtpq9sax45j49qa623vtl6fu6djjrjzm05w48l8srt78dz 

I think it's just to stop "bait and switch" abuse of polls, but there ought to be a warning as it's not at all obvious.

It's also not consistent either, because you can edit the main part of the post without resetting the poll.