Although I also take issue with labeling people "stupid," I also take issue with the blanket assumption that people are victims of the media environment. Both take away people's agency in their own way.
Instead, I'll ask this uncomfortable question. What if a good chunk of these people would prefer to believe a convenient lie over an inconvenient truth? If so, what does that say about them and their morals? Is that better or worse than being labeled stupid or a victim?