That's all fine but that's what I'm getting at with you overthinking everything. On a VJ and speed forum when someone says "black" they're generally not referring to Kenyan americans. I think you knew that. When the OP mentioned dancing he's not referring to professional dancers or anyone whose ever received professional dance training. Take a group of untrained people and have them dance (or do any other physical maneuver) and you get a look at what type of people are inherently good at it and which ones aren't. Same goes with artwork or any other skill. There are exceptions to everything but look at general tendencies.
i'm overthinking it because you're so dramatically underthinking it that you're actually completely wrong. why i'm still arguing with you is a mystery as you're basically ignoring what i write.
your argument -- and it's by no means unique to you, obviously; it's a pervasive stereotype -- boils down to: "i have seen these people who jump high and are fast and also they are black, as defined by me. therefore, black people are, in general, naturally able to jump high and fast, as compared to whites or other races/ethnic groups."
close analogue: "black people are incarcerated at higher rates than other ethnic groups in the US. therefore, black people are inherently likelier to commit crimes than other ethnic groups." same thing.
or another close analogue: "children of recent chinese and korean immigrants often excel in school. therefore, in general, they are naturally smarter than other ethnic groups."
also, i know what the OP meant by dancing and my point was that people who are good dancers are people who started practicing dance as little kids. not all of those people started out with ballet or got professional training, duh. some of them just always danced: they saw adults dancing at family parties, so they danced, too. then, when they got older, they didn't look like complete fuckups dancing at parties. that seems much more likely than your argument: "stereotypical nerds, as defined by me, are usually not good at dancing and tend to overthink things. therefore, less intelligent people, also as defined by me, who i declare don't overthink things as much, are better at dancing." that makes no goddamn sense.
i mean, it's entirely possible that all people with skin tone and facial features that fall into the U.S.-invented category "black" are more likely to be good leapers and runners than people whose skin tone and features fall into other parts of the spectrum. and it's entirely possible that dumb people are better dancers than smart people, as defined however you want. but i doubt it.