nDad is an alcoholic.
I approached him about his drinking problem and he denied having one, said he can quit any time he wants, etc. Right next to him there was a restaurant-sized garbage can full of Patron, Jack Daniels, and wine bottles.
There was literally a mountain of evidence right in front of him, and he denied having a problem.
In some of our "debates" about socio-economic injustices--he is a hard right-winger--he has straight up said, "I don't care about data and evidence and what the experts have to say."
Exchanges like these and others with him and other narcissists have taught me that justifying, arguing, or defending, or explaining your decision to these types is completely futile. They have no desire to learn or grow; they just want to impose their beliefs on others.
Despite this, I still think we should engage with them in public spaces, not to convince them, but to convince others. It's to expose their bullshit. We should continue fighting the good fight. But behind closed doors where it's one-on-one or you against a group of Ns? Don't waste your time.