Comment by ants_everywhere

I think you're underestimating the role deliberate propaganda has played in mass murder.

Propaganda and ideology were a major part of the Nazi rise to power.

Marx, Engels, and Mussolini were all in the newspaper business. Jean-Paul Marat's newspaper was very influential in promoting the French reign of terror, including some claiming he's directly responsible for the September Massacres. Nationwide propaganda were major priorities day one to Lenin and after him in Soviet Russia.

Similarly with the Cambodian genocide, Great Leap Forward, Holodomor, etc.

Propaganda even played a big role in Julias Caesar's campaign against the Gauls some 2 millenia before social media.