because you get dozens of idiots posting stupid polls.
plus 90% of polls arent really polls, just the poster trying to back up a point.
i.e.
Poll: Perk the la7?
A. Yes, perk the la7, I'm sick of the dweebs
B. No! Us dweebs could never live without the la7!
Polls would probably be good to have, but they get annoying fast