Things can be just as bad, if not worse among men. Our logic astounds me.
If you are shorter I can pick on you 'cause you are weak, and if you are taller then I'll pick on you to prove that I am just as strong. ^^'
Seriously though, this happens to everyone. We're the proverbial hunters, taking advantage of our prey's weaknesses. It's one of our more primal instincts to see smaller individuals as less of a threat.
I am not really sure how the interaction between women occurs, since I am not really a woman, ^^' but I think it happens to everyone to a certain degree wether you are male or female.