Driftglass gives a pithy summary of the American variant.
…like any other cult, Republicans have conditioned themselves not to respond to external realities any more. Public embarrassment doesn’t work because Republicans have killed the part of their human souls that is capable of being embarrassed. Bringing down a hellfire of facts and figures doesn’t work because they simply will not recognize facts or figures from non-cult members as legitimate. Same for appeals to reason, to history or to basic human decency. Hell, citing their own words back to them from five minutes ago when their cult believed the exact opposite of what they believe now will elicit nothing more than a cow-dumb stare, followed by a smirk because, Bwhahahah!, they just owned you snowflake.
But then I see their analogs everywhere: the doltish Brexiteers, Fraser Anning and his gang of thugs, and I’m willing to bet we can find similar examples in the non-English speaking world. And then there are the anti-vaxxers, who may not be Republican at all, but who see the slow painful deaths of their own children as a triumph. It’s the Zombie Apocalypse, and it has crept up on us unawares. Only we don’t get the easy out of shooting them in the head, because they’re still human.