How does mass thought control work?

I'm not talking about brainwashing on a personal level but more about things large-scale propaganda, censorship and bribery.
I doubt brainwashing on a personal level is really effective but I do think it's certainly possible to control public opinion on a large level.
I think its more of a, if your job depends on not knowing something it's not possible to convince someone otherwise, then a hypnosis thing which seems more like a larp to me.

pic unrelated