Unsubstantiated claim. He is used as a negative advertisement of Soviet era.
If you read carefull the trial in Nuernberg, Germany was not punished at all and they were worse.
For me he showd disrespect for his comrades. The battle of Kursk had much more casualties that it needed to be. The same happens for the war in total. He was completely incapable to be a leader. Useless and he did not care for his country. He also demonized communism and was in reality a dictator that pulled the right strings to become leader of a party (exactly what happens with leaders usually). He was also a racist and mass exterminated people. If he was different may the bloodshed of WWII would be prevented.
But the same was Pinochet and the western media covered all his crimes.