Thanks. I think you've missed my point entirely. I'm well aware of the visa restrictions. My very first visit to the UK and at Heathrow our Qantas jet arrived just behind a flight from Lagos. They were examining passports with microscopes!
It's about putting people into thought buckets based on perceived race or ethnicity. I recommend Hans Rosling's book Factfulness, as well as the associated Dollar Street site.
These both challenge common perceptions. I've travelled extensively and thought I knew a lot about the world. Within the first few pages Rosling convincingly demonstrated that I was wrong about many things, and embarrassingly so. Chimpanzees making random selections did better!
Well worth a read. In the end, Rosling is himself put in his place by an African lady.
I love books that encourage my mind to examine itself. I think you'd find it worth a read.
Or there are excerpts, TED talks, websites, that present the same material in segments. The book tells a coherent story, in order, and is extremely readable.