If your great-great-grandfather participated on the Confederate side, and you hold some sentimental value to that, and you want to fly the flag and hang their picture up in your home, that's fine. But it should not be on anything that taxpayers pay for, because taxpayers are a part of the Union, not the Confederacy.
It's a totally different spiel when I talk at Morehouse. But when I'm talking at MIT? At the University of Cincinnati? I'm telling white people, in order to stop systemic racism, you must first befriend, become a colleague of, get to know intimately, put yourself culturally in the framework of someone who doesn't look like you.