FAnboys. Yes, I played Half-Life 2. Yes, I played it on PC. No, I don't think it was God's gift to gaming. No, that does not mean I have horrible taste in games.
Yes, I played Halo: Reach. Yes, I enjoyed it. That doesn't mean I'm a consoletard who wouldn't know a good game if it bit me in the ass.
Also, people who hate game companies unreasonably. For example, I can understand disliking EA, due to the whole DRM debacle, but why does everyone constantly scrutinize every decision and every sentence that leaves Bioware with a magnifying glass just because they are now owned by EA? They've made one game that actually has a broken fanbase, and that is Dragon Age II. However, the same company made Baldur's Gate, Neverwinter Nights, Knights of the Old Republic, Jade Empire, and Mass Effect. All those games are nearly universally enjoyed. And the same thing with Dragon Age: Origins. But DAII is apparently the worst game ever made, despite the fact that it is quite playable, so all of a sudden, people are reading up on Mass Effect 3 news just to comment and ***** about how Bioware's going downhill because of EA.
TL;DR: Fickle fanbases, and people who assume the parent company is 100% responsible for any decisions their companies make. Also, cake.