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.
Yes, I find the same goes for ads for example and addiction to social media etc. I'm not denying both are a problem in society but I don't like the assumption that everyone is equally affected by it or when people use it as a ready-made rationalisation for something im doing.
I also think your point can also be extended to say that generally right-wingers are also way more susceptible to it, even if to some extent we all are.