Because it's a wannabe sport. I actually want to watch real sports, like UFC or NFL. In UFC and NFL, people can actually get hurt, and that's what some people, myself included, want. I personally don't want to watch two gorillas manhandle each other with millions of braindead fucktards watching them.
Yeah, we know tv shows and movies are fake. But wrestling used to be a combat sport, which was never staged. From gladiator battles to Pride Fighting Championship, spectators saw ass-whuppings and loved it. Granted, people were killed in gladiator battles, but still. It was real.