>"I’ve never professed to be an expert on Muslims. Other people, you included, do that on my behalf."
I am not sure Rockrose does- more likely meant he/she thinks you think you are.
For the record, in case you weren't sure, I do not think you are an expert, and I think some others would agree with me. You do give the impression you know more than most but modestly say that's because others think you are, but maybe that's because you tend to remember better the favourable comments.
As for your OP, no I, don't think Boris should apologise or receive diversity training unless he wants it