Steve:

Would you consider a compromise such as using green makeup, rather than black? That is in keeping with the disguise aspect of the tradition and in my view would be better than dropping the play entirely - once you do that, it could easily disappear altogether. It reminds me a little of that old rhyme:

Here lies the body of old John Gray
Who died defending his right of way
He was right - dead right - as he walked along
But he's just as dead as if he'd been wrong.

I agree entirely that claiming this is racist is misunderstanding the tradition, but the fact is the pub owners' (or whoever) are the ones with the power here and if you think the tradition is worth preserving, its up to you to find a way of doing it in the face of such obstacles, however ill-founded.