In the case of Justin Trudeau, it was insensitive - and he is right, he should have known better - but it was 20 years ago and to suggest that he should resign seems over the top to me.
The Black and White Minstrel Show is a different thing entirely. I watched it too when I was young but I had no awareness of how hurtful and insulting it was to black people - or why it was so. It is deeply offensive and I think it was quite right to drop it.
As for the Morris dancers, no racist motives were, or are, intended by the blacking of faces. However, as a black panellist on Jeremy Vine said, blacking of faces has some very degrading connotations for black people. I agree with Giles Brandreth who said that if it hurts people's feelings, why do it? Why not use another colour to signify the need in past times for workers to hide their identity?
This is an extract from BBC's Children's Newsround:
"Blackface was a practice in which black people were mocked for the entertainment of white people, and negative stereotypes were promoted across the US and Europe.
"In the early 19th Century, white actors called minstrel performers used to paint their faces black and do comedy routines about black people, which were racist.
"They would do insulting impressions of black people in very exaggerated ways - for example, mocking their accent.
"These depictions were inaccurate, hurtful and deeply offensive, but many white people saw it as an acceptable form of entertainment.
"Ben Holman, a campaign worker for the organisation Show Racism the Red Card, told Newsround: "This practice in particular came at a time when black people wouldn't be allowed on stage due to their skin colour."
When black people are directly asked if they find certain things offensive, they often do not reveal their true feelings for fear of being labelled "touchy", "over sensitive", "having a chip on their shoulder", etc, etc. I have recounted in previous threads how, when my husband first came to the UK, his white colleagues said they would change his name to make it easier for them to remember (he has a very simple name but they wanted to impose a typically English name on him). He refused and was labelled "awkward". Most of his non-white colleagues went along with this re-naming because they didn't want to be similarly labelled.