I think it has become more of an issue in general as the discussion of software projects has moved away from mailing lists and newsgroups to blogs and other more centralized discussion forums.
I recently saw similar censorship happen at Opera's blogs. I would read some of the comments one evening, and there'd be some good discussion about features that the newer versions of Opera's desktop browsers are still missing. They weren't always positive comments, but they'd be relevant and remarkably civilized given the circumstances. Then I'd read the same blog post a day or two later, and entire discussion threads full of useful content would be gone.
Criticism and negative discussion is often the most valuable that there is. It often highlights real problems that need to be solved. To delete such commentary is not at all helpful, and actually probably quite harmful.