It's just one of my many pet peeves. I can understand having a dislike for Activision in general, but if you're going to hate, hate the right people...
If you hate what was done with MoP, or Diablo 3, or Starcraft 2, then you hate what Blizzard did. I'm starting to think Blizzard "merged" with Activision for the sake of a free and easy scapegoat to avoid that kind of ridicule.
Hell, when I go to the Activision site, I see that they're supposedly responsible for Call of Duty: Modern Warfare 3. Do people hate CoD?