There is no excuse for racism whatsoever. No-one living in this world came into it from choice. No-one is what they are from choice or because of anything they did to be created the way they are. White people did not choose to be white, nor did the parents from whom they came and so on back through the centuries. We all just turned out the way we did because of who our parents and previous generations were.
No race, nor skin colour, no nose shape or type of hair etc. makes one person superior or inferior to another person. Those kept down in life by people who 'think' that they are superior will bare a grudge and that might make them seem unpleasant but there is a history behind people being unpleasant very often.
I love black people although I am white and all my ancestors were white (to my knowledge) and no-one in my family has married someone black. If black people were to behave nastily to me for some reason I would, probably, not like that individual black person but that would have nothing to do with the colour of his/her skin. I've shared a room in college with a black girl. I've worked with black people and mixed with them, male and female and, for a short time had a black boyfriend (which upset my parents). I treat all black people in exactly the way I treat white people. If a white person was rude to me or cheated me etc. I'd feel the same about them as I would if a black person did that.
Discrimination of any kind, based on colour alone, is evil, nasty, hateful, vile and totally unnecessary and all racists should be absolutely ashamed of themselves and should change their ideas and ways of treating others.