Nazi Germany invaded the Soviet Union on June 22nd, 1941 for three primary reasons. First, to prevent the Soviet Union from invading Germany (according to some historians, Hitler beat Stalin by 24 hours) and thus to save Germany and Europe (and the whole European civilization) from being conquered, occupied and destroyed by the Soviet Union.
Second, to obtain Lebensraum (‘living space’ for Germans) to make Germany self-sufficient in food and key natural resources. And third, to make the Soviets (Russian, Ukrainians, Byelorussians, etc.) servants (or even slaves) of German colonists and indirectly of other Germans.
The first objective was, naturally legitimate and noble. The second and third objective were, obviously, outright criminal.
However, it did not really matter. Because Nazi Germany simply had no other choice but to invade the Soviet Union. Because given the immense resources of the Soviet Union and Stalin’s firm commitment to conquering Europe) the only way to save Germany and Europe from this existential threat was to destroy the Red Army with a lightning-fast strike – the blitzkrieg.
And that’s exactly what Adolf Hitler did. Yes, he ultimately lost World War II – by committing way too many way too serious strategic blunders. But he did save Germany, Europe and the whole global human civilization from destruction by Stalinist Soviet Union.