A big part of the element not being discussed is money. Less people who use Apple products probably means less page views for Daring Fireball. I don't think it was a coincidence that the focus of his enmity has turned from MS to Google since Android became a threat to Apple's most financially successful products.
The same goes for Marco. I expect him to have a bias towards Apple and developers because he makes his money off of Instapaper for iOS and he is a developer.
Gruber is a very talented writer but we all can be colored by how we get our paychecks. I will say that he amuses me which is rare among the blogging cynics.