Why the hell do "big girls" feel its alright to insult skinnier girls as often as they like?

I am 21 weight 100 pounds flat. and wear a size zero. The fellas like it cause im about 5'3 they say i look Like a barbie. Despite the complements from them ... I always get insulted for being my size. I love thick girls and i do not hate on them at all but they do it to me. I cannot gain weight i tried! I even got my doctor to give me medicine to increase my appetite. but the med. had over 30 side effects so i stopped. I now accept that this is the way God made me. I am against ppl losing weight to be a zero or starving themselves or throwing up to lose weight. I think thats ridiculous. All woman are beautiful, all woman are not made to be thick and all women are not made to be small. Did you know its harder to gain weight? its easier to decrease and intake of food than it is to force an appetite.Its not fair girls self-esteem is at jeopardy! the same feeling a girl gets when she thinks she is to big is the same feeling a girl gets when she is told she is too small. leave us alone!