What do you say to people who say "Crossfit is dangerous"?

I've heard many times that Crossfit is "dangerous" but I can never find any research on this .. recently I had a friend who trains say that the assault bike is dangerous and "ruins your form". I was like huh?? Maybe if you use it wrong sure... but I know people who have done Crossfit for many many years and are fit, healthy, look great, and rarely ever had an injury ... SO, what do y'all reply to people who say Crossfit is dangerous??