The news here is not encouraging. In the face of entrenched social divisions, there’s a risk that presentations that carefully explore both sides will be counterproductive. And when a group, responding to false information, becomes more strident, efforts to correct the record may make things worse.
Such "validators" are people you would not expect to hold a contrary view, so you cannot immediately dismiss them. Small cues like appearance or food preferences or background can have a disproportionate effect in subverting expectations like this. The logic is "if someone like THAT says it, maybe I should rethink."
Can anything be done? There is no simple term for the answer, so let’s make one up: surprising validators.