Agreed, and that applies to threads about any and all topics. It is possible to discuss the most sensitive of subjects without resorting to insult and ad hominem attacks. I'm just sorry that the anonymity and cover offered by the internet seems to make that a rare occurrence. For example, I frequent a local blog that is, by and large, a reasonably civil place. But, one or two commenters invariably respond to questions or disagreement with personal insults and attacks. This sends the thread off the cliff because, try as we might, it is very difficult for most of us to ignore venomous attacks.
Things are not that bad here, by a long shot. But, I have seen comments clearly written as innocuous expressions of fact or personal preference, including my own, draw nasty attack responses from people who apparently cannot tolerate someone who doesn't see things exactly like they do. Why someone who, in effect, likes vanilla ice cream feels the need to skewer someone who says he likes chocolate ice cream is a mystery.
As for threads that go off track, does the site's software give mods the ability to move threads to other forums?