People hate Rashad for a lot of reasons going back a long time. Here are some of the big ones
-first impression- most peoples first impression of him was acting like a spoiled buffoon on TUF and refusing to fight. All the TUF champions have backlash but Evan's seems to be more warranted.
-fight style- he has no problem laying and praying to win the fight and the decision
-fight selection- While guys like Griffin, Ortiz, Liddell, Jackson, and Jones court support from the fans Rashad doesn't, instead he goes out and tries to beat them. He also makes it clear that he won't fight teammates, for a while it seemed like the Jackson camp was using Jardine to "test" fighters for Rashad.