Glorianny
As for the issue of audience members being offended and that being their own concern, to what level would any of you like to take that argument. To the level where blacking up is OK because it's only black people who are offended? And if not where do you draw the line? It seems to me that if one particular section of your audience is offended by what you say (and that might be only one person) then you have a duty to apologise to them. If what you intend to say is known to be offensive to a section of the people you wish to speak to, then you should expect the organisers to take steps to ensure what you say will not offend them, and, if you cannot assure them of this, to be stopped from speaking. Especially when young vulnerable people are involved.
I am offended by blacking up, (and I am white). I don't think it is only black people who would object.
If a performer blacked up at a university - and (crucially) if they did so in a non-satirical way - I would expect the student audience to make it clear that they found it unacceptable. Which is different from having a spokesperson decide how they should think and ban the performer.
If, OTOH, a speaker was talking about the history of people of colour in the media, and blacked up to show how it worked, or was satirising the way in which white actors were chosen to play the parts of black characters, I would expect students to be intelligent enough to know the difference between this and support for the practice.
The idea that if one person in an audience is offended the organisers should apologise is, IMO, daft. Nothing would ever be performed again, as there would be no time left for the performance. I find a lot of comments on TV about so-called Boomers (of which I am one) offensive. The comments are often inaccurate, lazy and inapplicable to the majority of people in the Boomer age group. Should there be an apology every time someone makes such generalisations? What about comments about young people? Benefit claimants? Northerners? Southerners? Graduates? Second home owners? The vaccinated? The non-vaccinated? etc.
Finally, having worked in universities for most of my career, I would agree that students are (on the whole, but not exclusively) young, but would argue that they are no more or less vulnerable than any other section of society.