Why You Gotta Be So Mean?

I hate how people are so judgemental. They will make fun of somebody because of something they say/do. For instance, there is a girl that I sit next to in Language Arts, who is scruffy on the outside, but really nice. They call her fat, smelly, and everything else under the sun. People will make fun of me because I'm short. I'm in 7th grade and only 4'6". They call me short and annoying. It really hurts somebody's feelings when they are made fun of. Most of the people who make fun of a person don't even know them well! This leads me to not understand why people have to be so mean.