This makes me hopping mad. Exactly who do they think will be 'offended'? Unless some black people actively object and say they're insulted (which of course they haven't) then why is it necessary to change a long-held tradition? There are border Morris sides with different colours on their faces (Red Leicester for example) but they too have long traditions of doing so.
My husband is black, as many of you already know. He always goes to the Morris festivals and has had his photo taken with many black-face sides. He thinks it's all absolutely super, and would be horrified if people thought he was offended!