The black ability at doing *anything* in an organized manner is soooooooooooooo great that every civilization that has ever made even a half-assed attempt at conquering and exploiting black populations has suceeded.
White abilities at key "white" playing positions, particularly QB, so far exceed their nearest black competition that arguing about the quality of each teams ball carriers is almost a moot point. Culpepper and McNabb are about it for your theoretical black team, nowhere near the Whites we could name, and frankly, you better hope Culpepper doesn't get injured.
With the best White QB and OL you could get, playing against a team where blacks would be doing all the mental work as well as the physical, I believe the White team might just about scrape up a win with Stephen Hawking carrying the ball.
I'm not denying that a mixed team which uses the strengths of all would be better than all-white or all-black, though. The relationship between Whites and blacks in football is akin to that of men and horses in pre-Modern warfare. Certainly the armies who used the physical abilitities of the beasts had an advantage over those who did not, but just as certainly, no army of horses ever staged a sucessful campaign against men
The bit about Latinos being the best baseball is absurd btw, and an insult to many past players both White and black. On average they possess neither the tremendous strength of Whites (esp. true in the pre-juice era) nor the sprinting speed of blacks. What they bring to baseball, like boxing, is alot of grit and the sheer numbers in which they try to enter the sports, not inconsiderable qualities but it doesn't make them a race of super ball players.
Claiming the MLB Latino importations are because of some innate superiority is like claiming the illegals in the resteraunt's kitchen are there because they are innately superior at washing dishes.
Basketball is an interesting case. Black dominance there
is part biological, but no doubt part cultural as well. It does favor the freakishly tall and long-limbed, who are a larger % of the black population than the White, and sprinting speed no doubt helps. Then again, there are many tall whites, Whites equal or exceed blacks at vertical jumping ability (as demonstrated by Olympic High Jump), and are just plain better than blacks at throwing every kind of object for both distance and accuracy-footballs, baseballs, javelins, shotputs, etc. So no doubt you'd see more Whites in it if they were encouraged, instead of actively discouraged, from playing.(I've always said raising the net a few feet would help, make it more about throwing skill than being a genetic freak.)