Why does it clash? After WWII and the start of the Cold War, the world stage had radically changed. Some world powers had been diminished while others were ascendant, and plans were redrawn.
The specific claim that's likely false is that the Soviet Union, as early as 1941, planned to conquer Europe (as part of some bid to implement "world communism") and specifically attack Germany, and that Hitler's Barbarossa was some sort of "preemptive/defensive" strike. The first goes against Stalin's philosophy at the time, the latter goes against what we know about Red Army readiness and also what we know about Hitler's racial ideology.