Fans aren't very receptive when he intercepted the ball he didn't celebrate with with his team, in fact he ignored them, and sprinted off the field, ripped off his helmet, stood on the bench, faced the the alumni section and taunted them. He was out to prove something from the beginning, as he should have been, but he, or his wife shouldn't be surprised when it wasn't received well.
Luckily, it was all on TV, so he and his family have a momento of him acting like a total tool forever. It wasn't some terrible act of sportsmanship, but is did give fans reason to act like fans, and any other fan base would have done the same.