Hell no. Unless stuff is blantantly illegal, abusive, profane, or just downright stupid... leave it alone. These types of threads generate quite a bit of attention which tells me that folks want to know what others think. Besides, a good argument never hurt anyone.
As a moderation crew we do pretty damn good at keeping things from getting out of hand.
I think a better guideline would be to contribute to a threads topic vs. slamming a threads topic just because it's been posted before. If you don't have an answer or a contribution and it turns into a hot topic then just monitor it and step in with the occassional clean-up/warning/ban.
One of the main reasons people really like this forum is because it's not elitest or condescending... a place that makes even the least XP-erienced member feel welcome. I think if we started closing INNOCENT threads just because we're bored with the topic would take something away from xp-erience.