So in Putin's telling the expulsions, mass murders, rapes, and famines, of 1910-1950 either didn't really happen or were just minor mistakes.

Sadly, they did and until very late in USSR that was minimised or completely denied in the official history. So people nursed their grievances, passed them down through the kitchen table, told their kids not believe the teachers, told their kids to smile and learn Russian. Told them one day, it will be our turn.

Putin (and tbh most Russian's) understanding of their immediate neighbours excludes their rawest and most important unresolved history.

That's dangerous and tragic. Countries like Ukraine and Poland who's partisans committed terrible atrocities can and do just blame Russia instead of owning that responsibility. Russia also provokes them every time it errects another Stalin statue or similar.

Russia in turn reacts to every criticism or attempt to limit it's influence as a plot by "enemies" as these are "little brothers" it protected and industrialised (even though in fact most were significanly more developed than Russia pre-WW2). Poles have been treated so kindly by us, if they say these things it is the CIA. Or NGOs, gays, whatever.

I'm not saying the CIA doesn't do it's best to inflame this. But can I tell you everytime a Russian nationalists opens their mouth on RT it does a thousand times more. No one wants to end up like the Volga Germans, the Karelians, or the Kazan in the 40s. And unlike the average Fox TV viewer they have learned those names at school.