Isn’t propaganda just a form of persuasion? What about propaganda separates it from advertising or interpersonal communication?
Edit: Not all propaganda involves lying. For some reason, we seem to be more comfortable with a person lying to us than we are with viewing a propaganda poster that uses verifiable facts.
Edit 2: Another interesting note is that in some countries, propaganda is not viewed negatively like it is in English speaking countries.
Propaganda has always held an aspect of dishonesty, though, either subtle or egregious. It’s never been looked at as more than a tool- like how the Roman historiographers used it to paint their neighbors as barbarians. (Thereby justifying extended wars. Which… were not cheap.)