Because that's the way it is!
Actually, since the leotard has almost universally been accepted as a women's garment with little exception, i.e., wrestlers, gym workouts, boxers garb, stuff like that....you know, macho stuff, the male version of the leotard for dance/ballet nowadays, more than likely looks like the more macho version of application of such.
I hope this either clears things up, makes it easier to understand or totally confuses you.
That's the way I see it.[/i]