Interesting. Definitely contrary to what you would think. But The Heritage Foundation is a biased source and the numbers are pretty old. Could be interesting to see some new ones. Also the 75% identifying as whites in 2004 is in the entire population - not young people, which is the relevant demographic here.
How is the Heritage Foundation biased when it comes to military demographics?
It is general orthodoxy in some quarters that the military uses the poor and minorities as cannon fodder. This myth dates back to Vietnam, when the economic angle certainly had some elements of truth but the minority one didn't and doesn't. Anything that points out that these assumptions are wrong, as demonstrated by dead0, are called biased.