It's a combination of the three, humans as a whole love to complain. The internet is a great place to do it because you're anonymous. I think it also comes from a superiority syndrome kind of thing, they think if they spot "Problems" and whine about them it makes them "Better" than blizzard and anyone who doesn't agree with their view on the "problems."
Logic and reason are nearly completely absent, easiest example is a person with 9 level 90's posting the other day about how he doesn't have the time to do dailies and it ruined the game for him. Which is kind of funny because they are not REQUIRED and if you have NINE level 90's already then you obviously have quite a bit of time to play. Even if the game was changed to be exactly what they asked for they would instantly whine about something else.