The rape and pillaging is Darwinian survival of the fittest and is old as humanity.
The cross breeding of the slav and cossacks into the German gene pool has produced a current population that is docile and unwarlike. The fit have prevailed.
I was watching a History Channel documentary about the fall of Berlin, filmed in Britain in the 1970’s. One male survivor recounted that two Russian soldiers burst into his apartment and demanded, “Frauen, Frauen!”. Thinking quickly, he showed them to an adjacent apartment, which contained the remains of two recently deceased German woman, killed in the fighting, one in her 30’s the other in her 80’s. The Cossacks looked at the corpses, blessed themselves, and departed without further comment.