Covid denier, climate denier, election denier, science denier – are all bandied about to immediately end debate,  tar any difference of opinion as literally insane, and depict anyone who ever disagrees with you as stupid and evil.  This epithet is now even being used pre-emptively to makes sure that no matter what anyone who now or ever questions the move to ban gas stoves will not be doing so based on facts or logic but because of their "gas stove denialism."

Like so much woke terminology, the initial meaning of the term is far removed from its current usage, though it has the distinct advantage of being generally familiar, allowing it to be "Trojan Horsed" (admittedly, some arise sui generis) into public discourse.

Common usage of the term "in denial" (besides the joke about the river in Egypt) seemed to come to the fore mostly in regards to an inability to face up to an obvious, almost always, personal truth.

In denial about your drinking, in denial about the fact that your kids are actually monsters, in denial about your sexuality (nothing to do with today's genderpalooza) and on and on.

But, like in almost every case in which the woke have stolen a term from the self-help/therapy movements the term has been utterly bastardized.  For example, trigger and safe space are now used in the opposite way of their initial intent – see here.