I'm generally very pleased with our experimental enabling of comments. Nonetheless, I want to stress to people that we reserve the right to remove comments, in our own discretion (and the converse right to be busy enough with other things that we don't bother removing certain comments even if, given enough time, we might have).
Rudeness is obviously one cause for removal; a comment's being off-topic is another. But we may also remove comments in some other situations, for instance, when someone frequently posts things that are chiefly rants, fairly wild exaggeration, or invective (even without the use of major vulgarities).
Our goal is to provide an interesting and pleasant environment that can help inform readers. To do that, we'll occasionally have to exercise our editorial discretion. Naturally, there's always a risk that this discretion will be used erroneously, no matter how well-intentioned the editor. But I think that discussion groups (especially on the Internet, but also off it) generally need an editor who'll occasionally make such judgments.
And, remember, it's a big Internet. If you think we were mistaken in removing your post (or, in extreme cases, in removing you) -- or if you prefer a more free-for-all approach -- there are surely plenty of ways you can still get your views out.