Why do people take this film seriously?

How can people see a kid shouting "pancakes!" while doing slow-mo kung fu moves and think it's supposed to be serious? How can people see a dude getting a harmonica rammed down his throat and think it's supposed to be serious? How can people see a cop who's surrounded by dead bodies but is more concerned with throwing a party and think it's supposed to be serious?

Cabin Fever is hilarious, and I don't mean that as a backhanded compliment. Cabin Fever is genuinely gutbusting, and was clearly intended to be that way. The dark humor reminded me alot of something you'd see in South Park, where ridiculous things are happening but it's being portrayed with a straight face. The characters are all clearly meant to be self-aware cardboard cliches, and it's hilarious to watch them succumb to their own stupidity. It's a movie where the cliches are acknowledged and self-aware, and begin to attack and kill the characters. I will never get how people, especially from the time of its release, saw this and thought it was a genuine straight-forward horror film. Would Cabin In The Woods be mistaken as a serious horror film if it came out in 2002?