I think its something twisted in the human condition that keeps these age old racial animosities alive.
For example,in my forty years on and off working in urban schools,I have seen way more INTRA racial hate and anger than the other way around.Black kids will pound the crap out of each other,harass black females and call each other the worst kind of names but as soon as a Mexican or Asian does something against a black kid,its on-the blacks all unite against “the other”.
I went to all white schools.Most white kids talked bad about”the niggers”but would run away real fast if they saw four or more blacks together.The big prejudice back then was against Jews.Lots of the Italian and Irish kids didn’t think much of the”kikes”.Jealousy in my opinion.The Jewish kids dominated the honor rolls in the same ways Asian kids do today.