Skateboarding is a performance sport, like gymnastics, figure skating, sychronized swimming, diving, etc.
Also, skateboarding is mega dangerous if you are overweight, heavy guys don't tend to take odd angle falls very well (you have plenty of cushion, but your bones aren't any stronger), and we tend to break the boards pretty easily.
I tried to take up skating again at 19 at 210 lbs, and I broke 3 boards in a week and gave up. I tried again at 240 and 25, and broke the board in the first 5 minutes.