Answer:
Why do you think African American involvement in the American Revolution is often overlooked?
They were overlooked because at the time that the American Revolution took place, the vast majority of African Americans were slaves, and even if many of them participated in the revolutionary army, their condition as a group of people (as African Americans) was that of half-citizens: people who many deemed inferior to White Americans.
Where else might you see this happen within our history?
African Americans were even more involved in the American Civil War, with thousands of them fighting in the Union Armies, specially after Abraham Lincoln decreed the Emancipation Proclamation. Their contribution to the Union victory is often overlooked as well.