The Nazis based their entire philosophy on misinformation, and they did this in a world that predated computers. I don’t actually think there’s going to be a problem here all of the issues that the people are claiming exist have always been possible and not only possible but actually done in many cases.
AI is just the tool by which misinformation will now be spread but if AI didn’t exist the misinformation would just find another path.
I disagree with your point that it wouldn’t get worse. The Nazi example was in fact much worse for it’s time because of a new tool they called the “eighth great power”.
Goebbels used radio, which was new at the time, and subsidized radios for German citizens. AI is new, faster and more compelling than radio, not limited to a specific media type, and everyone already has receivers.