I don’t think it’s ignorance at all. In general, I’ve found them quite capable of reasonable discussion and grasping the corrected concepts and facts which would undermine their worldview.

It’s just that none of it matters.

Conversations a day or two later will be indistinguishable from conversations before the discussion. They return to tired old tropes because they’re repeated in their social circles, and because they’re comfortable to embrace. It’s not a matter of intellectual rigor or even ideological devotion. It’s just attachment to the familiar.