Why is the South so racist?

I am orginally from New York and I moved to Georgia when I was 14, Texas when I was 15, and Alabama when I was 16 ( Yes, I moved a lot) and now I am 17 back in NY and everything is back to normal but while I was at these states the house I lived with my parents were robbed, I received threat letters from the neighbor's children who were my age, I was laughed at my cles for being the only hispanic there, confederate flags being shoved in my face, they even broke my dad's car window with a baseball bat one night and wrote "Go home N*ggers" with spray paint on the car. Why are people from the South like this?