Those people were ethnic Russians but were born in Ukraine and were Ukrainian citizens,many had served in the Ukrainian army they were quite happy to be Ukrainian citizens until Bandera infested the minds of some Ukrainians and they started killing and attacking other Ukrainian citizens who for the most part were ethnic Russians, it isn't black and white as you make out, over two million Ukrainians fought in the Red army in WW2, over three hundred thousand fought as anti Nazi partisans, as for keeping Nazi soldiers for ten years those bastards got off light.