UHH, it has nothing to do with fighting styles, ego. It's got to do with something else entirely.... and I don't have time to elaborate!
A few reasons... 1) His unwillingness to face the very best. 2) How deluded he is. He could have had a TRILOGY with Manny by the time he got him in the ring! He took the whole of '08 off when the WW Division was on fire, then came back and fought a fat LW in his comeback (and still mossed weight). Never faced Winky, Margarito, Sergio, GGG, but would campaign in these classes. He genuinely feels that he is the greatest because he went undefeated, yet when you point out others who retire undefeated he shoots them down. Kellerman said it best: NOBODY thought that Floyd was TBE when RJJ was around. Lewis, RJJ, Toney, Loma, Holyfield, Manny, Hopkins etc. There's been MANY fighters around when he was around that I rank higher than him.
Floyd is hated for the same reasons that other fighters that get hate for. He talked a big talk but didn't walk a big walk. Like Golovkin once saying "Anyone from 154 to 168" or whatever he said. Floyd constantly contradicted himself. Honestly look at his resume. There is not one single fighter on his resume that, AT THE TIME HE FOUGHT THEM, knowledgeable fight fans said : That guy is a killer. I personally discredit any catchweight fight for the guy that dictated those terms so accounting for that, and the time at which he fought most fighters, his resume is not really good. I'm not just picking on him though, modern boxing is all about "marinating the fight" and once you get the fighter popular, your fighter dictates everything. I appreciate guys like Shawn Porter who is a nice guy (not highly skilled unfortunately) but he fights ANYONE and usually gives them hell. Floyd played boxing the right way though... controlled the risk and preyed on moron boxing fans who ended up paying a lot of money to see him fight the likes of Berto, Guerrero, Ortiz and a few other "Never was" fighters. Pro boxers probably hate him for that too. dude made over half a billion dollars fighting poor opposition and was able to walk away from the game fully intact. Who would you rather have been post fight career Ali, Foreman, Chavez or Mayweather? Easily Mayweather.