Why are some people so cruel when it come to weight(repost)?

So i just got done watching Revenge of the Bride maids and there's a scene in there where the Aunt from Sabrina calls Raven Flabigl just because she's a little bigger than everybody else. And when i heard that i got pissed, because you're a little doesn't mean you're not healthy, i mean it all depends on how much you're overweight, that is. But still.