Organ donor rejected....

[John V]

Credit for getting a good source. However...

Blacks/African Americans continue to experience the most severe burden of HIV, compared with other races and ethnicities.

Blacks represent approximately 12% of the U.S. population, but accounted for an estimated 44% of new HIV infections in 2010. 

Do they let black people donate?

First, you need to rule out black MSM and give us the resulting statistics for this to be meaningful.

Second, a correlation with a known mechanism, as in MSM, is much more compelling than a correlation alone...unless you're suggesting that black people spontaneously develop HIV.