I think this is a specific example of a general trend: As peoples interpenetrate each other, the phenomenon also known as multiculturalism, they are exposed to each others' belief systems and traditions. There is a lot of information out there, and not only is a lot of it wrong, a lot of it is not understood correctly, a different kind of wrong.
So blacking up in England is interpreted similarly to blacking up in America, which was a tradition which is not poorly thought of. This conflation leads to resentment.
There is a multi-hundred years old tradition among the Dutch called "Zwarte Piet". It is not a thoudand years, and it is based on a book, but it is beloved among some, and now under attack.
In some cases maybe an explanation and education suffices. But in others, some traditions deserve to be kiboshed no matter how old they are.
Note the announcement in the United States just within the last two days that the grandest circus in American history is going to go defunct. This has gone on for almost a century and a half.
And the tradition of bull-fighting has been diminishing over the last few years and it is certainly over a thousand years old with major religious connotations, both pagan and Judeo-Christian.