The racism in America stems from our governmental support of slavery long after it had been outlawed by Europe (and first by the UK). To make matters worse, instead of painting the Confederates as traitors (which they were by definition), he welcomed them back into the Union…and so they had an opportunity to keep their former slaves from gaining any real independence or economic wherewithal. The result was nearly a full century of Jim Crow laws (analogous to apartheid). By the time the 1964 Civil Rights Act passed, racism was so deeply ingrained that the segregationists that they even began a school system for whites — the “segregation academies” — started by our family acquaintance (you can read some about it here). Even in 1984, the only doctor’s office in a nearby town still had separate entrances for “white” and “colored” — and having been raised there, I thought it was normal. I should note that the aforementioned “family acquaintance” was Sen. James Eastland, twice president pro tempore, and who was for a generation the most powerful racist in America. My family loved him. My grandmother once worked for him selling moonshine (yes, moonshine) in his plantation commissary.
Slavery was officially ended by the Thirteenth Amendment to our Constitution, and as with all other amendments, it had to be approved by at least 2/3 of all other states before it became effective. The 13th Amendment quickly became enacted after the Civil War…but a lot of Southern states didn’t ratify the amendment for a long time. In fact, my home state (Mississippi) was the last one to officially ratify the 13th Amendment…in 2013. Yes, six years ago. I should note that many of those in Mississippi state government are the sons and daughters of those who fought against civil rights in the 1960's.
All this boils down to the fact that the political mess you see in America is all about race. Religious and cultural differences are but excuses. Race is the reason. However over-the-top that may sound, I believe that to be factually accurate.