Why do racism exist

Why racism exist I think it is that one thing is color some people do not like the color of an other person if they do not have the same skin color and some people is still on slavery and how the whites use to treat the blacks.And their intelligence level.They pick on your size how big you are and how small you are and racism is on how you look in fasion any thing to bring somone down people hate people for nothing they do not have to know the person hate is just there people should not judge a book by it cover and that what people do if you do not know that person you should not judge him or her they can be a good person but people look at them as someone that should not be on this world. People even judge you on your clothes shoes anything that they can bring you down clothes do not make you you make you and any body can do and learn any thing they put there mine to. So thats what I think about whats going on in this world with racism.