The problem with propaganda is that it generally fails to last historically. There are notable exceptions which are recognized to be B.S. by advanced scholars and which are still commonly held to be "true" by the general population. The idea that people believed the Earth was flat before Columbus for example.
More recently, people ignore the fact that the Democrats are politically responsible for multiple genocides. Andrew Jackson the first President elected as a Democrat after the Democrats changed their name from Democratic Republicans, committed genocidal atrocities against both African Americans and First peoples. More recently, most democrats in Congress voted against the 1964 Civil Rights act.
If we go further back, we can examine the propagandistic concept that the Church was responsible for the Aristotelean theory of the Geocentric Universe when the conflict between the Church and Galileo/Copernicus was really an academic conflict between the prominent educational institution and some researchers challenging academic cannon. At the time of the Renaissance the Catholic Church was the primary publishing house, the primary provider of education and the primary religion of Europe.
Or we could examine the idea of the "Dark Ages" where people claim "the entire world was plunged into intellectual darkness by religious fanatics" when in actually it was only Europe. Priests in Europe have always been Scholars and many priests have been responsible for educating researchers (like Copernicus and Galileo) and/or researching new ideas. The biggest problem after the fall of the Roman Empire was that Rome sucked at technical documentation and excelled at religious and political documentation. Technical information was passed along by word of mouth through apprenticeships. As the technical experts responsible for amazing achievements like the aqueducts, the Colosseum and Roman roads died off the technical lessons learned by those experts died with them. The practice of maintaining technical secrets (closed source technology, ala Microsoft) creates a potential for a similar collapse. Fortunately Open Source addresses that and minimizes the potential for a "dark ages" should a cultural collapse occur.
So, while many of these issues are understood by various advanced scholars, these propagandistic ideas still permeate our education and academic circles.
It would be cool to see what people believe about the worlds political leaders of today in a thousand years, the differences between what is taught at lower and more advanced academic levels.