Blackface (and Brownface): What's the problem?

The reactions from the general public expressed on phone-in programs and in newspaper comment sections to the Justin Trudeau brownface and blackface incidents strongly suggest that many people honestly don't know about the history here--don't know why it's a racist act for a white person to wear blackface. Yet many columnists and editorials, instead of recounting that history and explaining things, have merely referenced it briefly. For any who don't know the history of the minstrel shows and so on, a very good overview is provided in a June 11 2018 piece published in The Conversation. Entitled "The Problem with Blackface," it's written by Philip S. S. Howard of McGill University. Here's a link: http://theconversation.com/the-problem-with-blackface-97987