Disclosure: I am an Apple fan -- but I absolutely will not defend the practice of purging negative comments from community forums. I think censorship is probably the single most frustrating experience anyone can have in a forum, warranted or not. I speak from experience: I've been censored recently as well -- in an entirely different forum, and for reasons which seemed entirely unreasonable to me. Ironically, I had made the egregious error of trying to help.
In responding to a thread about a bug, I described one software development methodology (scrum, if that matters) to a crowd of discontent gamers in the Steam forum. I then painstakingly crafted a reasoned explanation for why that process necessitates that this particular bug in an older game (Half-Life: Opposing Force, which had been recently ported to both Linux and Mac) simply won't be fixed anytime soon, because the Steam developers are almost certainly entirely wrapped up in the development of Half Life 3. I then went on to speculate (and I suspect this is where I went wrong) that as soon as we see a fix to that bug, we should all be on the lookout for the impending release of HL3. A short time later, that entire thread had suddenly vanished from the Steam forum, with no explanation.
And the problem crops up elsewhere as well; forum admins are frequently overzealous, especially when they see something that they view as a potential slight to their corporate overlords. It's a very unfortunate trend, and as I see it, the only way to avoid being unreasonably censored is to post your comments elsewhere, where -- hopefully -- unbiased management will leave your commentary on controversial matters intact. (Slashdot might qualify as such a haven... I know I haven't been censored here. Yet.)