Apple works very hard to cultivate an image of "our users are hip, cool, creative, and free." Apple also specifically avoids controversy often going out of their way to take non-positions, so to speak. At that level, no advertiser should take the maintenance of that image lightly for what would be a cheap bump in the discussion trends.

That'd be my guess, at least. I imagine we'll know if we see the ad pulled (if it hasn't been already).