the number cbs posted could be part of an attempt at a bad joke - 88 is associated with nazism, and 87 is used frequently as a joke to imply that.
as far as the sharpton ralley, i watched bits and pieces of it on cspan’s replay. I didn’t really listen, as the speakers advocation of being repressed, and needing more economic and social help made my blood boil - some of it was short of outright demands for reparations. From what was shown, I would estimate the crowd to be no more than 400-500, and that would be counting the speakers and performers, also. That’s right, only a few hundreds. I have some screen captures as the camera pans the crowd (except for greater than 90 degrees from infront of the camera - meaning anything behind the camera) and there was no where close to the 3 thousand people as reported by someone in the washington post. if there were people in the stadium, they were not shown on the pans that I saw, so I have no real idea how many may have been up in them.