I'm guessing it's more a matter of overcompensation than anything else. Boys get a lot of grief for choosing a career in dance in our culture, particularly ballet, but once they're in the ballet world they're pampered, relatively speaking. The girls face even greater competition, there are more of them, they have to work harder, don't get the same chances at leadership roles like choreographer, etc. It's easy to see how these circumstances might turn toxic.