I agree completely. The concept that no truths are absolute and thus my truth is as valid as yours is a virus that has infected western civilization.
Look even at conservative Christianity. The rise of nondenominational megachurch Christianity is a post-truth movement.
Doctrine used to matter. There are many issues where things are either true or false. Today insisting on those things is “uncool.”
I should not have laughed when I read the last line of your post “Today insisting on those things is ‘uncool’.”, but I involuntarily snorted, even as I knew EXACTLY what you meant...
I only WISH it were uncool. I could embrace that.
But instead, “insisting on those things” makes you a science denier, flat-earth enthusiast, Nazi, sexist, Luddite, holocaust denier, and, as an overarching term to cover everything...
RACIST!