Maria is suffering from the embarrassment of riches syndrome. Right now she seems to have it all and some people don't like that. I think most of them, however, are people who see Maria stealing the thunder of their favorite players. She went largely ignored by many of these critics until she convincingly beat Serena Williams at Wimbledon. Suddenly, she developed villain status almost over night. Now, even the most innocuous move on her part is soundly criticized, i. e. John Wertheim's attack on her for her hideous fist pumping at Staples Center. You would have thought she'd flipped Serena the bird the way he talked. All she did was pump her fist after the allegedly injured Serena had hit winner after winner, following a five minute injury time out.
And don't forget, this is the same Serena who constantly belittled Maria's Wimbledon victory, implying it only happened because Serena was playing at 20 percent or some such nonsense.
Maria is not perfect and I am not particularly a fan of her's, but I think bad behavior should be a lot worse behavior than Maria is guilty of before the press starts taking them to task publicly.