The phrase "Apple fanbois" is disparaging against the fans themselves, but not against Apple. If your brand is successful enough to have fanboys, then your brand is successful and that's a good thing for you. The fanboys themselves are irrational, and deserving of some criticism about their irrationality, but that generally does not carry over to the brand itself.
Under certain circumstances, having brand fanboys can be a bad thing for the brand, since they can ghetto-ize the brand to the point where the casual buyer won't buy it, to avoid being associated with those people.
Comic books are the first example that springs to mind, but I guess Harley Davidson might be another good one.
