I didn't even comment on this specific case. I just wanted to point out that, contrary to what you claimed, John Gruber have in fact criticized Apple quite a bit, and especially on the topic of their App Store regulations. To claim that he always agrees with Apple is simply either uninformed, or a lie.
Yes, Gruber is generally decent (except when it comes to Android, where he seizes every available opportunity to make snide, petty, uninformed remarks).
But everyone else here is talking about this specific case, which, as you suggest, seems startlingly out-of-character for him.
He is sometimes critical, true, when the critical mass goes against Apple, but his sneering pro-Apple stance 99% of the time is insufferable. It seems like 50% of his posts are about iPad competitors.
I didn't say he never disagrees with Apple. I said that he frequently does agree with them and that he often goes to absurd extents to justify positions that seem contrary to common sense. I said that he used tortured logic to arrive at these positions, and that he can be counted on reliably to agree with Apple.
Glenn Beck occasionally disagrees with the Republicans too but I bet I know how he'll vote in most elections.