It all goes back to their announcers. I watched the game on an internet feed with the Rockets announcers and they were horrible. Total and complete homers, but besides that they whined constantly about phantom fouls that they thought should have been called. Or when Artest shoved LeBron at the end of the game, they said "LeBron doesn't like it when guys shove him much like that, I wish the Rockets had more players like that who are tough and physical". They argued that it shouldn't have even been called a foul. The entire game the announcers made it seem like there was a conspiracy against Houston and that all the calls went against them. Fans are already inclined to believe that when they root for a good team, and their team gets outmatched. It's easy to blame the refs, and when the announcers are feeding that too, it's obvious what the results will be.
