I went to the Baseball Hall of Fame this past Columbus Day, and there was a group of Black school kids there, from NYC. They were attempting to engage in rowdiness, but every time they reached a certain level, one of the chaperones would crack down on them, but quick. The result was that these kids got to enjoy a great experience, and everyone else got to see that excuses for ethnic shenanigans are just that - excuses. I approached one of the leaders, as I was leaving, and told him he was doing The Lord’s work. His complexion was too dark to tell, but I could have sworn that he was blushing, as I walked away ;)
And it sounds like that was what was not happening in this case.
The museum didn't ban the kids, it banned the school, meaning it banned the adults that were supposed to be supervising these kids but weren't from bringing any more groups of them in to run wild. I imagine they'd welcome back any of the individual students that knew how to behave in a museum, and would do so.