I have a problem with moshing when it becomes a macho man, who-can-knock-down-who contest, or when the scene kids come and swing at the air. Can't we just leave it as a personal choice like whether or not to use drugs or whether or not to lubricate? It's right for some people and not for others. What makes it any more stupid than headbanging, other than the fact that The False Profit pointed out, that it disturbs other concert goers? If you don't want to mosh, chances are you won't stand anywhere near the mosh pit, which can still be very enjoyable. I've been to many shows standing in the very front row and not being disturbed my moshers... and others where I was in the front and had my knees ground to a pulp on the 2 foot high stage (worth it).
Moshing, for some, can maximize the experience of being at a show where fast and angry music is being played, and nothing more. And for others, it's just stupidity. I can see where both sides are coming from, but at least have the sense to know that both are right and both are wrong