Yes, I think there's a bit of a misconception out there. Nothing seems to indicate that it was banned or controlled in period, except that it may have been more expensive than most other colors, and culturally I think bright colors were more highly prized.
But it's also possible that there is a fear that if they allow black, then almost everyone will use it, when instead at an event there should be a much higher proportion of other colors.
I also suspect that the modern avoidance of it may have come about at a time when there was less information about it, so people tried to stick to what was more well known. Once a "rule" is there, it tends to persist.
So it could be a lot of different things.