I think it's mostly because people laughed at Wii when Nintendo showed it off (developers, journalists and fans alike), and said Nintendo were done for and hailed X360 and PS3 as the true innovators ... And then when they were proven dead wrong, very few of them want to admit it, so they try and put the Wii down at any chance they get.
This isn't the case for all people, of course, but yeah, it's the general cause for most haters, I think.









