I mean no insult to the black troops who fought on both sides during the Civil War but what the man was saying is demonstrably untrue. Memorial day began when a local school teacher in Petersburg, Virginia, took her students (white, of course and that is sad) to Blandford cemetery in Petersburg, Virginia and they placed small American flags on many of the more than 30,000 graves of unidentified soldiers that were killed in Petersburg and buried in Blandford cemetery. Many of those troops had been brought from around the south to defend Petersburg, one of the last blockades to reaching Richmond and many were white and many were black but since the race of any particular soldier couldn't be determined, flags were placed on as many as possible.
The wife of a Union General happened to be visiting and saw that and convinced her husband, who held a position of power (again, white and again, sadly) to begin doing that for all of the unmarked graves anywhere in the nation of unidentified soldiers killed in that war (and with more than 500,000 dead, many of the dead were never identified). By the turn of the century, a day was chosen and made a National holiday in which all soldiers killed in any war would be honored. I mean no disrespect to black people but no, Memorial Day was not begun by black people and the NAACP is, in this case, mistaken and seems to want to stir up racial issues over something that never happened.
Where were they in the 1980s, when the KKK held a march on the main road through Colonial Heights, a city that borders Petersburg, and black baby dolls were dragged along the street with nooses around their necks? That was a horrible incident that happened not all that long ago.