Where does Racism come from

I think racism comes from mankind.We can only blame our selves.We judge curtain race for the things that one person does.We stereotype them blame them.Just cause someone who looks like them did something wrong we start blaming the entire race.I'll give you an example.One time in Chandler.Cops started to round up Mexicans.They rounded up about 50,000 Mexicans.They said that they were going to deport hem.Right there just cause they were Mexican they thought we were illegal.More then thirty thousand Mexicans were legal and they sued for millions of dollars.