Ugh, obviously a high school is not the kind of place to go dancing around naked but I do not see any reason why you would press charges. Nudity is something completely natural but the way the states goes about it quickly links it to sexuality. Nudity doesn't have to be sexual.
It's silly how the world changes based on your location. I surfed in France for a couple of summers and recently I've been surfing in Australia (Victoria). While changing into a wetsuit in France nobody gives a fuck, there's nudity on a regular basis. In Australia: No nudity what so ever, they've even got these funky towel robes thingamajigs over here which help you change. Being nude in public seems like a mortal sin here.
I wouldn't surprise me if because we're generally more exposed to more female nudity we're more likely to experience male nudity as something sexual. Therefore I would guess that male nudity near children would be punished more severely. No data, just a gut feeling and I could be completely wrong.