Yes, I liked Shriver's article.
I find it interesting to put it in the context of my own reaction to About Kevin. I think I was in an unusual space as a reader - I have someone I'm very close to whose son is a psychopath (not a mumsnet armchair diagnosis, this is the diagnosis of the crim. psych. on his offender management team) who has committed serious crimes (admittedly not mass murder). I could see what Shriver was trying to do, but for me it rang totally false. This was not how the real woman I knew reacted in the real circumstance. To that extent, for me it was an act of appropriation of someone else's life, and one which failed, but not one which I wish Shriver hadn't attempted to write. But (here's the thing) I think Shriver failed interestingly. As Shriver herself says, most will fail. The aim is to fail better!
For me, as a bad writer (of fanfic - hence arguably guilty of appropriation twice over!) the issue of characters serving plot and wider ideology is also interesting. There's an old adage in the newspaper business: "Dog bites man isn't news. Man bites dog is". Fiction is a bit like this - it's the extreme, the unusual, the different which catches our imagination, both as writers and readers. Should, for instance, a writer who identifies as feminist never write a book about female on male domestic violence simply because statistically it is rarer than male on female (or indeed male on male) DV? I'd say no. Any topic is up for grabs. And fiction, at the level of individual books, deals in the specific. It's the opposite of "feminist class analysis." But at the same time, class analysis of genres - collections of books, types of writing, does have its place. I'd want the space open to critique, say, crime fiction as a genre for disproportionately focusing on rape and sexual violence against women (often written with the intention of eliciting a sexual frisson, which I find unforgivable), or pointing out the number of times the author lazily reaches for the cookie-cutter character backstory of "violent rape murder committed by man who turns out to have had sexually repressed refrigerator mother/sexually abusive mother". (No, really? Again? Have I ever seen this in actual reporting of criminal cases in real life? Erm, no. So why does a group of authors collectively keep peddling this horse shit?)
So I guess for me the answer is critique the author - brutally if needs be. Sometimes people deserve a good drubbing in the review columns for writing crap which promulgates stereotypes. (But you should always have taken the time to read the whole book, or listened to the whole speech, not flounced part way). The thing that should be utterly and totally resisted is going down the line of censorship (or of creating a cultural climate where self-censorship starts to take over).