Welcome to Librarium Online!
Not sure if this has been posted before but I can't see it anywhere.
Basically, I've seen a few threads recently that have been dead for months, and have been put back up to front page and thus been posted on, due to the poll being answered., I have done it myself once without realising, and its happened quite a few times recently. I'd suggest somehow making the polls automatically end after lets say... 2 weeks of inactivity within the post? This would stop old posts being necrolysed due to poll votes. Hope you agree, and sorry if this has already come up or is already known about 8Y.
This topic has come up before with the mod team. I'm not sure what the coding of the site allows, but I'll try and find out. I agree, it's annoying and I don't like the thread-bumping without a new post.
That said, there are some polls hat we let remain simply because they are all but perennial. The old "What's your bloodline?" in Vampire Counts or the Wood Elves' "What color do I paint my army?" Those crop up so often, we tend to just let them stay; plus, it's kind of cool once a poll has a ton of votes.
But in general, yes, it's a pain.