Don't get why they would hate someone responsible for 66.6666666666% of their national championships.
The best coach in UF history abandoned them after the worst season of his career, and they've been bad-to-mediocre ever since. It may sound paradoxical, but the 2 national championships contribute to their resentment. It was a long fall from that peak, and they can't process it.
(Imagine what some commenters here would sound like if OSU goes 7-5 this year, Urban leaves for a season, and then returns to coach Notre Dame to a national championship.)