That was just to ensure a fair competition. You never know when someone is wearing performance enhancing clothing spun from golden fleece, or otherwise blessed from gods. It was the anti-doping movement of its time.

I was joking anyway. But yeah I knew about the olympics not so much celebrating nudity

I mean, it makes sense to celebrate athleticism by showing off the athletes' bodies. But yeah, a lot of the Greek myths have people either in the nude or just barely clothed. To be fair, in the Greek summer it makes sense to run around lightly clothed.