From the article:
Stalin's great purge (1936 to 1938) took a punishing toll on the professional officers of the Red Army. Many talented, but outspoken, officers were dragged off to the gulags of Siberia for re-education, or in other cases simply shot as enemies of the state. This resulted in a state of perpetual fear among those remaining military officers.
Each company also had a political komissar, as part of the dual command. The climate of fear caused by the purges meant the military officers often deferred to the komissars, despite the komissars being civilian Communist Party officials with little or no military training. This resulted in some rather unsound military decisions.
The Russian soldier has traditionally embodied stoicism. They were Tough, loyal soldiers able to endure the most extreme hardships of campaign and battle with not a word of complaint. This attitude has continued into the Red Army.