At least the west country Carnivals, most notably Bridgwater, made no rationalisations, justifications, or excuses for decades of blatantly racist blacking up.

It was simply a culturally acceptable manifestation of the inherent racist norm of the era.

I can't vouch if it has completely disappeared from carnival floats in this hopefully more enlightened 21st Century,
as last time I watched it about 15 years ago I froze my bollocks off standing in the cruel winter rain and wind,
and haven't bothered since...

I've a vague memory they might still have been dressing up as 'comedy pantomime' china men and mexicans...???