And that I find somewhat bizarre.
Trying to understand this, you may have heard of the Windrush generation of black people who arrived in the UK from the British commonwealth in fairly large numbers. They quite changed the face of Britain from almost entirely white to one that was very mixed indeed - about 30% of the kids I went to school with up to age 11 were black, in an area that had been previously working class white. The 2 ethnic groups didn't mix much with a few exceptions*, and probably because the white population was not welcoming, the black newcomers held tightly to their cultural differences, quite reasonably. That created a very us-and-them situation, and I wonder if this was one of the things that sent him down this path. It may also be that he could collaborate with black musicians from other nations because they would accept him as he was, and so he could accept them?
*I had a black friend at school, but we lost touch after going to different schools aged 11. I heard he went to prison for murder later on.
Because of the area I grew up in, it took a long time to see black people outside of their cultural barriers that had been built, and to see them as people like us. The culture was so defining and hard to set aside in everyone that I met, especially after puberty. I had never been brought up to be racist, and the barriers came through interraction rather than my own culture. I was also the son of a foreigner in that culture, subject to a prejudice that I can see and understand now, but didn't at the time.