I'm almost done with it and as someone who grew up 'Pure' and managed to largely self-extract from christian fundamentalism / white nationalism Haidt is about 30 years too late. His book seems like a largely self congratulatory attempt by a non fundamentalist to steel man the arguments of 'The Pure.' Which incidentally is the name for some baddies in a sci-fi novel I finished recently, apropos of nothing. Maybe the last 15% will change my mind, seems unlikely though.
His point is that rational argument is not the most convincing rhetorical strategy when conversing with the faithful or conservative, not that one side is right and the other side is wrong. I recognize that me bringing this up to you is just me wasting my time; you are still "pure" and still refuse rational argument. Your every rhetorical gambit comes from a place of "ours is the one true blood" you've just foresworn your birthright. So we'll keep talking past each other because you've chosen a weird demographic: those who fundamentally believe fundamentalists are evil and are utterly incapable of rational discussion about rational discussion.