Why do people just absolutely hate Slipknot?

Now, I am not some overly-enthusiastic "maggot", but I really like Slipknot. I know they're not the best, but they are (or were) rather good and I don't see why people just call them absolute crap all the time. They are (or were) way more original than other nu-metal bands like Disturbed or Mudyvane or whatever. So why do people have to hate on them so much?