I think you greatly overestimate the state's interest in hiding the violence they perpetrate, and underestimate how little people care about their country using violence, at least in this country and many eastern ones.
In revolutionary France, as part of the purge of the old monarchy and replacement with a republic, there was a need for a more efficient way of killing people. See, the people wanted to kill all the old royals, but the old method was hanging, drawing and quartering, which besides being labor-intensive and incredibly painful, often used a stand-in in place of a rich nobleman. They wanted something more humane, more egalitarian, and of course, more efficient, since they had a lot of people to kill. The guillotine was introduced, and from Wikipedia:
"Its operation became a popular entertainment that attracted great crowds of spectators. Vendors sold programs listing the names of those scheduled to die. Many people came day after day and vied for the best locations from which to observe the proceedings; knitting women (tricoteuses) formed a cadre of hardcore regulars, inciting the crowd. Parents often brought their children. By the end of the Terror, the crowds had thinned drastically. Repetition had staled even this most grisly of entertainments, and audiences grew bored."
During both the Russian and Chinese revolutions, death tolls of those executed as traitors or proponents of the old empire were published widely by the state. After World War II, traitors were again executed in great numbers, and even during the war a "blocking detachment" might stay behind the lines to execute any deserters.
America has also had public execution pretty much since day one. Hanging was our preferred method before the electric chair, and then lethal injection. We make sure that both the families of the victims can witness these deaths, as well as other witnesses, and they're widely covered in the news media. We are still the only Western nation left that practices capital punishment, mainly because people here love it so much that they can't seem to pass a law banning it or follow the UN resolutions that ban it.
Now, there's plenty of abuse doled out by oppressive regimes against their people. But this abuse is still not necessarily propagandized or even hidden. A state may use secrecy and intimidation to continue their abuse, but propaganda is used more often to bolster some case the state is trying to make. Anyway, in modern times it's far more common for corporations to use propaganda to defend themselves from democracy than for the state to use it against its people.