If they want to dig for a tie, they have a (very weak) point. The black and gold is Calvert, but the red and white is Crossland. The Crossland was used by Marylanders who fought for the South, and the two were combined in a new flag in 1880 to unite those from opposite sides of the war. Since the goal of the Ctrl-Left is to divide us, I expect them to destroy the Maryland flag specifically because it is a symbol of unity.
Actually the it’s the banner created by Lord Baltimore. The yellow and black were from the Calvert (father’s) coat of arms and the red and white from the Crossland (mother’s) coat of arms. Had nothing to do with slavery what so ever. The fact that secessionists used the Crosslands portion of the the banner is irrelevant to the history of the banner.