Why do people have trouble accepting that LeBron will be the greatest of all-time and hate on the Heat?

Shaq won Kobe's first 3 rings for him. After that Kobe demanded to be surrounded by all-stars, otherwise he demanded a trade. A pretty expensive team the Lakers got there, but everyone hates on the Heat. They have 3 all-stars now and will win many titles. LeBron personally guaranteed it in the celebration they had last year. But instead of accepting that, people hate on Miami Heat fans. I used to like the Spurs and the Celtics before when they were better, but nobody was hating on them like the Heat.