Putting aside the fact the worst examples of "Cancel Culture" are an amplified, tiny number of edge cases, given fuel by those who wish to attack fairly reasonable requests to marginalise hate speech.
Ishiguro makes a good point a skilled writer can write from the perspective of someone very different from them. Not that many people are actually arguing against that. What was of concern is the perspectives of marginalised people being written in a cliched and harmful way by people who have no understanding of their lives. Or because they have an agenda of portraying those people in a negative way. Understanding built on accurate and intelligent writing is great but I'm not going to read stuff that has an agenda to caricature and attack.