People get very passionate about this topic, but basically it comes down to culture.
The tradition in the States is to cut (and, as I understand it, there are doctors who are very well paid for offering a simple service and so make sure this continues). In most of Europe, including the UK, the tradition is not to circumcise.
Both types of cocks are fun to play with, in different ways.
I would not want to be cut, but that is because I am used to being uncut. There is often a silly argument mentioned about uncut cocks not getting washed. That may have been the case prior to the invention of baths and showers, but I have never come across a partner with a problem there.
I have, occasionally, met people whose foreskin didn't retract. They would have benefited from some medical intervention. But those cases are few and far between (no different to those people who really should have had their wisdom teeth removed, but it wasn't high enough priority for them).
To go back to the original question, I have indeed noticed more black guys in the UK being cut than the average for the population. Mostly due, I think, to the culture and tradition of that group, as well as a load being from Muslim backgrounds. This extends to a lot of black/white mixed race lads as well, for whatever reasons.