I've used Macs for years, and I suppose you could call me a Mac advocate, given that I run a Mac-related website. However, I thought chromatic's comments weren't delivered in a flame-baiting manner, nor were they out in left field.
He was writing about his experience as a Linux user who liked Apple hardware but felt that OS X was not as effective for his needs as Linux. He detailed his particular reasons, then described what his experience with Linux on Apple hardware was like. He took pains to point out that his preferences were his own, and that he wasn't out to bash OS X or Mac users.
It seems to me that it's useful to get feedback like this from time to time, particularly since so much discussion of OSes quickly degenerates into mindless bickering.
I'll keep OS X on my PowerBook, but I certainly wouldn't want chromatic or anyone else to be forced to use an OS they don't enjoy using. I always thought one of the fun things about being a Mac user was standing up for freedom of choice.