The history of racial superiority in America

I am very interested in learning a lot of things and always keep an open-mind to matters that most people would not even bother. As for me; I am recently paying attention to scientific discoveries and the history of the world. Right now, I am watching a little about how it was years ago here in America especially during the time when the Ku Klux Klan (KKK-for short) did a lot of atrocity to people that were other than whites (people of colors I mean, and Jews). It was really sad those days as the people were so unbelievably uncivilized. So much so that many lives were lost including someone who stood up for what is right Dr. Martin Luther King, Jr.-an American clergyman, activist and prominent leader in the American civil rights movement.
My, with all the atrocities in the world; people do ask if there really is God who supposedly watching over everything. It seems that people kill in the name of God more than anything I have ever heard. Religion is serving both the good (as it keeps people in line) and the bad (as it makes people commit crimes). There are a number of examples like the Ku Klux Klan that believes in racial superiority shouting "White Power!!!" that has a history of killing non-white people, religious people who actually took their lives (in mass suicide) to go to heaven sooner and meet God, those people who decided to murder their children so they won't sin and be able to enter the kingdom of God and those who continues to kill in the name of God (human sacrifice).
I tell you I can't even imagine how terrible it must have been to be living in the society those days when equal rights and racial equality was not yet possible. People suffered so much from being maltreated, belittled, and looked down upon and worse of all brutally murdered just for having the wrong color of skin. I am glad that there are not too much of it going on nowadays. Although those people who believes in racial superiority are still very much around up to this day. The only thing is; they are blending in the crowd anymore as they don't wear their costumes that make them stand out. I guess since it is more civilized now, they are not as open as before. No one can tell who is who to be able to pin-point; otherwise there will be lashing out and violence because of their violent past. I can't understand why people who are supposed to be Godly act so ungodly. They don't practice what they preach. I hope people will settle down, live and let live just as they should. Enjoy life and do the right thing so the world is a better place for everybody.