'you are not immune to propaganda' is true but sometimes the way people deploy this particular soundbite reveals a complete unwillingness to attribute any agency or ideology to people who espouse some pretty heinous bigotry.
like there was a post going around recently talking about people whose parents became increasingly radicalized by fox news and it had one of those tumblr style comments on it along the lines of "REMEMBER! THIS COULD BE YOU! You are not immune to propaganda either. STAY VIGILANT" and the implication here is always that right wing radicalization is something that somehow happens to otherwise pleasant people without their consent or knowledge. But perhaps some of you guys just need to grapple with the fact that your parents might be more bigoted and reactionary than you want to believe.
nobody is immune to bad information ecosystems or groupthink or poor science or anything else that makes radicalization possible, but i do think the idea that anyone is just a bad news pipeline away from supporting white supremacy does a lot to let white supremacists off the hook. it's the same kind of line of thought that gets people to talk about how bad things in fiction shouldn't be 'romanticized'. its a kind of worldview that operates under the implicit belief that a human being is a vessel being uncritically filled with whatever you pour into it and does nothing to grapple with what the actual appeal of these far right talking points is to the sort of otherwise ""normal"" seeming people that can be sold on them.