Lionel Shriver appears to not understand the argument, and instead seeks to demean it by redefining it as a petty concern.
Cultural appropriation - in writing at least - is better defined no more than this: writing badly and thoughtlessly about people and culture beyond the author's experience is no longer acceptable.
If it ever was this, it's an odd name to give it. How is bad writing by an author about people who aren't like the author "cultural appropriation"? It's bad writing, and should be criticised for being just that. Such writing is usually seen as bad because it uses stereotypes and produces cardboard cut-out characters, whose presence in a story can often be described as "token" when it isn't reinforcing the stereotype(s). That isn't appropriation; it's (bad) substitution.
Note the example Shriver gives: the complaint from someone who hadn't -- who refuses to -- read her book inspired by the treatment Shriver's own brother received because of his weight problems. (He died, to quote Shriver's speech, "from the complications of morbid obesity.") How can one criticise bad writing, or stereotyping, when one has not read any of it? Easy: declare it to be "not your experience". (I'm assuming -- I haven't read it either -- that Shriver's novel was not about being the sister of someone who is morbidly obese, but of being someone who
is morbidly obese.)
So this isn't about bad writing, but about people who want to control what other people say, not necessarily only about them personally, but about people who might be less 'Privileged' than the author.
It isn't as if those in the same silo are necessarily going to do a good job: there are lots of people who, at first glance, would fit in the same silo as me (white, male, adult, British-born). Only some of them** would do a good job of writing a character that would fit in that silo. And unless the only characters in the book fit in the silo, what are we to make of the other characters in the book who might be -- brace yourselves -- women, children, not white, born outside the UK? What if
only one character in the book ticks all the "cultural" boxes that the author does? Scandalous!
And to use
reduction ad absurdum: how long will it be -- given that radicals in other political spheres are known for their fissiparousness (hence all the left-wing and right-wing fringe groups and parties) -- before we're facing a mirror image of the infamous
"one-drop" rule: the "all-drop" rule, which declares that the author must have each and every attribute of the character (there
can only be one, obviously) in their book?
** - Someone who doesn't fit in the same silo as me might do a
better job than anyone who is in that silo.