A lot of it was the over the top promotion, hyping Ronda at the expense of other legit champions like Mighty Mouse or Werdum.
A lot of it was her absolutely god awful personality.
I've been following Ronda since her second amateur fight, and as an advocate of judo's effectiveness in MMA, I wanted her to win and keep winning. She lost me as a fan after her juvenile behavior on TUF and her fake skirmish at the weigh-in with Holly just confirmed my suspicions about her being an overall terrible person.