Most people aren't able to dispassionately pursue the truth. You need to remove emotional barriers first before the facts can be heard by finding ideological and emotional common ground somewhere and then using that camaraderie as an attack vector to convince them that something else that they believe is wrong. I have done that somewhat successfully with a fairly far-right person, managing to bring them back on some of their more extreme views.
It's possible you weren't the right person for this specific job. I believe that some alignment on at least some views is necessary for this process, otherwise the barriers just immediately go up.
Having said that, it's true that for some people no amount of reasoning or persuasion will work. The amount of cognitive dissonance and the extent to which the belief is tied into their self-worth and identity precludes anything but a years-long process of deradicalization. People aren't designed to be rational.
It's possible you weren't the right person for this specific job. I believe that some alignment on at least some views is necessary for this process, otherwise the barriers just immediately go up.
Having said that, it's true that for some people no amount of reasoning or persuasion will work. The amount of cognitive dissonance and the extent to which the belief is tied into their self-worth and identity precludes anything but a years-long process of deradicalization. People aren't designed to be rational.