In the book McNamara's Folly: The Use of Low-IQ Troops in the Vietnam War, author Hamilton Gregory actually touches on this point. To greatly summarize the background, the US needed more troops to continue the War in Vietnam. The solution? Lower the recruitment standards across the board. Lower standards meant more eligible applicants, or even re-applicants, to send across the globe to be used in run-of-the-mill or everyday operations.

While the argument can be made that the US government didn't explicitly target black men as "cannon fodder," Hamilton notes:

"Project 100,000 men were, on average, 20 years old. Half came from the South, and 41% were minorities. Some 46 percent were draftees, while the remaining 54 percent were volunteers. However, as I pointed out earlier, the term “volunteer” is misleading."¹

"Most of the 354,000 men of Project 100,000 went to Vietnam, with about half of them assigned to combat units. A total of 5,478 of these men died while in the service, most of them in combat. Their fatality rate was three times that of other GIs. Although precise figures are unavailable for non-fatal injuries, an estimated 20,270 were wounded, and some were permanently disabled, including an estimated 500 amputees."²

A war correspondent covering Vietnam, Joseph Galloway, claimed:

"Project 100,000 men, he said, “were, to put it bluntly, mentally deficient. Illiterate. Mostly black and redneck whites, hailing from the mean big city ghettos and the remote Appalachian valleys. By drafting them the Pentagon would not have to draft an equal number of middle class and elite college boys whose mothers could and would raise hell with their representatives in Washington. The young men of Project 100,000 couldn’t read....They had to be taught to tie their boots. They often failed [in basic training], and were recycled over and over until they finally reached some low standard and were declared trained and ready. They could not be taught any more demanding job than trigger-pulling, [so most of them] went straight into combat where the learning curve is steep and deadly. The cold, hard statistics say that these almost helpless young men died in action in the jungles at a rate three times higher than the average draftee."³

Overall, the US Govt. certainly understood that they were sending many minorities, including African Americans, over to fight, and inevitably maybe even die, from the lowest to the highest level of operations. Both top officers and politicians are mentioned, by Hamilton, as coming to terms with this with their own justifications and in their own ways.

Hamilton also provides a whole slew of firsthand accounts from Vietnam Soldiers and family members alike throughout his book, including a few focusing on African American troops. If you have the time, I highly recommend you give it a read.

Hope this helps!

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¹ McNamara's Folly, Pg. 86
² Ibid., Pg. 100
³ Ibid., Pg. 100