The answere to that is pretty simple: the more developed and less religious extrem a country is, the more white people are living there. Finnland, Sweden, Norway, Germany, Poland, usa, australia, or cannada to name just a few. All country's with a proportionally high amount of white people, all developed, and almost all are not religious extreme (I look at you usa)
Now name some country's that are developed, not religious extreme, and have a high or almost exclusiv population of black people. Well, I can't name one, altho iam sure there is one. Maybe jameika?
So Usualy, "black country's" have less connection to the internet, less ore terrible devices to record stuff, and face harder consequences of they are caught and Usualy are less likely to speak a non native language. All this contributes to a lower presence in forums, and therefore to the wrong conclusion, that zoo is a almost exclusive white phenomenon. I can assure you, it is not, I bet there is almost no difference in how mutch zoos are black or white.