I think there are both cultural equity (http://www.culturalequity.org/ace/ce_ace_about_ce.php) and cultural appropration (https://en.wikipedia.org/wiki/Cultural_appropriation) angles on this.

That the first gets respect and the second caution and/or disdain in the 'above the line' discussions here are part of what makes them a great resource.

I think that aspects of both are getting stirred into a incoherent mud in this discussion.

One thing that strikes me is that minstrel shows, and UK TV's 'Black and White Minstrel Show' in particular, included both and appropriation and lack of respect for a culture - that of African Americans. In the UK most black people are of Afro-Caribbean or African extraction. Are they offended by black-face and how much attention did they pay to the B&W Minstrel Show?

Lumping all black people together strikes me as as disrespectful.