Propaganda doesn't totally rob people of agency free will (more accurate term), if it did this site wouldn't exist. People do have the capacity to develop critical thinking, skepticism, and a basic curiosity about the world that allow them to develop some resistance to propaganda.
You can hold people accountable for failing to even attempt to do this.
Its soft determinism of likelihoods. Historical materialism speaks of classes, millions of people thinking this or that, but that just means 80 percent of them might think something in particular, due to life dice rolls being this or that in certain composition of class relations.
I try not to, i'm a dumbass in lots sorts of things. Anti-vaxxer who masks or lives in rural parts is completely different from anti-vaxxer in restaurant business/healthcare. One is cautious, the other is malicious person, intellect doesn't enter it
I agree there's mitigating factors, I for example don't really judge people from the developing world as harshly for being behind on certain social issues. I take those into consideration.
And if you really do try I applaud your for you consistency, but I'm suspicious when people on this site make this claim, I mean we literally have a comm called "The Dunk Tank" where we mock people for their stupid beliefs. When someone takes that mockery and tries to apply it more seriously then suddenly we're soft determinists who aren't superior to people who believe in the Great Replacement Theory.
Because people believing in great replacement theory take existing issues (falling birth rates due to worker hours/absence of socialized childcare, immigration workers hiring to dodge worker rights) and arrive at weird conclusions. Propagandists are obviously unreachable as they are paid to lower wages of immigrants, but people who believe in that stuff? they see issues, they can be reached. this is all of course in personal conversations, without peer pressures, and not a duty of marginalised comrades.
Re: larger points there are two sets (well lots more than two, but two groups) of heuristics of looking at the world: the elite one and the marginal one. The elite one is squabbling about who should be in the elites and the marginal is elites shouldn't exist (communism/anarchism).
The elite one is acceptable to the masses of workers as long as they deliver on something of livable standard (like why communists collapsed in usa after ww2), and following squabbling of slowly removing barriers on entry to elites to woman/blacks/lgbtq.
But fundamentally that system of deliviring living standards is unstable due to larger arch of history of capitalists profit drive, and we now entering the zone where they have consistently not delivering for larger and larger slices of population who start asking questions. Those questions lead them to all sorts of answers , some think its cause christianity, some cause one of the groups entered the elites, some cause outsourcing to china; some think cause thats what the capitalist system does
And larger point about of "they arrive at weird conclusions": oligarchs create information noise of "pick your own pet theory, any theory" except communist one. If all you ever heard of communism is usa history books, would you look at what those weird communist are saying in videos with low production values and 10 k views, instead of brightly lit studios with conventionally attractive hosts?
And even here if you decide to look at it, how likely are you to drop into some sorts of sectarian infighting with finger pointing