Why do people judge others?

I'm highly confused on why people (mostly popular people) make fun of and judge others, I get you might do it to feel better about yourself but that's not a healthy way to manage your self hatred you might feel. What do you get in return from picking on other people? All because they look different, act different, have other interests and beliefs doesn't mean you can make fun of them. It happens so much in life and I don't even understand why, you aren't living long enough in life, why make other feels sad just because you are? It's even worse if people just do it for the sake of doing it, that's worse than doing it to forget about yourself in my opinion. But I guess it won't really stop so there nothing I can do about it apart from talk about it. I appreciate if you read this!