"I think people deliberately using 'blackface' when they know full well that morris sides call it 'blacking up' are more interested in politcal debate than meaningful discussion. It's a cheap trick."

I really don't think terminology is the problem here. So long as they are putting black paint on their face, it is absurd to complain about someone using the "incorrect" term!

Many people would say it's irrelevant what morris sides call it. Most would also say that drawing a distinction between "blacking up" and "blackface" is risible.