I'd say it's from a complete lack of knowledge of the sport. Most people who turn on their TV and the first thing that's on is someone throwing their body at rails and off massive jumps can't really appreciate the technical side of the sport, it's almost mind boggling to watch.
When I used to watch the Xgames before I skied, I would only watch a run or two because all of the runs looked the same and I'd lose interest. A guy would start by making their way down a hill, hit a few rails, then a few jumps, and then there's a 5-10 minute gap between the next rider, which is how people who don't ski look at it.. However, skiing is on the up right now and there's a bunch of people getting into park, it'll be interesting to see where skiing will be in a few year's time and how much attention it gets after the olympics.