Lionel Shriver’s new novel, a hymn to inclusivity and kindness – just kidding – takes place in a parallel recent past as western civilisation withers under the grip of the Mental Parity movement (“the last great civil rights fight”), which insists there’s no such thing as stupidity, preferring to speak of “alternative processing”. Effects run from the retrospective cancellation of Frasier (because the Crane brothers are “brain-vain”) to tens of millions of Covid vaccine deaths (because newfangled employment practices stopped Pfizer hiring qualified staff, resulting in the inadvertent creation of a toxic serum).

World-building as trolling, basically. The saga unfolds in Pennsylvania from the point of view of a contrarian lecturer, Pearson, cancelled amid the war on wisdom after she bravely makes Dostoevsky’s The Idiot required reading – the very title being outlawed, natch – before being caught on camera ranting about “retards”; footage that sweeps through the press, who are more concerned with “cognitive bigotry” than with Moscow and Beijing rampaging through their neighbours “because the western world was wholly caught up in this Mental Parity fiasco”.

Pearson’s in trouble on the home front, too. When she calls her seven-year-old daughter, Lucy, the “D-word” – “dumb” – the girl rats her out to social services, who send her on a $569 course in “cerebral acceptance and semantic sensitivity”. The belief of her tree surgeon husband that she should drop the cultural renegade act and bow down to “MP” orthodoxy wilts, just a little, when he finds he isn’t allowed to assess his new assistant’s credentials, leading to a chainsaw incident followed by equally calamitous healthcare. And at the heart of the novel is Pearson’s 30-year female frenemy, Emory, a television presenter who cheerleads the pile-on after her public downfall.

Part of the book’s point is to lay Trump’s rise at the door of language-conscious liberals (“what qualifies a candidate for high office right now is... knowing absolutely nothing”) and I suppose you can’t fault Shriver’s commitment to the bit, which extends to pages and pages and pages of examples of new world order absurdity. Amazon won’t stock My Brilliant Friend for fear of book-burning activists riled by the title’s meritocratic implications. Benedict Cumberbatch is cancelled for playing the too-brainy lead role in Sherlock (“the debut episode fatally coincided with the near-universal ideological pivot... among the newly minted anti-intelligentsia intelligentsia”). The pejorative associations of “turkey” mean “domesticated gallinaceous bird” is served at Thanksgiving – and as for “sage”, well, “if we insisted on adding the conceited herb, ‘poultry seasoning with furry leaves’ would identify the plant for most people”.

For people who only think of Shriver for her culture war op-eds – it’s been a long time since We Need to Talk About Kevin – she’s always been a distinctively straight-shooting literary critic. Even she seems to sense that, for all the needle, this novel lacks verve or sass, stretching thinly dramatised ideas – political correctness has gone mad; we should worry about Putin, not pronouns – over nearly 300 pages. When Emory asks: “Why is this so personal for you, Pearson? So maybe there’s such a thing as variable human intelligence, and maybe there isn’t. What does it matter? Most of all, why does it matter between you and me?”, it’s as if even Shriver is beginning to lose interest, and we’re only a third of the way through. Pearson begins one expository tranche by telling us: “To my embarrassment, here I am relating picayune points of philological fascism – the death of the ‘dumbbell’ – while, out in the rest of the world, events of more considerable moment were afoot.” Another ends: “Transcribing this is tedious and depressing, so I think that taster will suffice.” Yup.

• Mania by Lionel Shriver is published by Borough Press (£22). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply