While Hitler certainly had an intense dislike of Communism, that wasn't be any means the sole reason behind the German invasion of the Soviet Union. There were also more practical things: land and resources. Germany in 1941 was creaking, she was low on many vital raw materials, her trade agreements with the Soviets were unlikely to be maintained much longer, as the Germans were already way behind in payments and had no way of making the shortfall up. If the German government wanted to maintain even the status quo, they would need to find a source of wealth and resources. And the only viable option was the Soviet Union. Then you have to remember the long term goals of Hitler's plans - to build Germany into a state capable of matching the USA. To do this, Germany needed land. Land that could only be taken from the Soviets. Without the "lebensraum" of the Ukraine and Western Russia, Germany could never compete with America. Finally, you can't overlook the fact that the Soviet Union was a threat to Germany - not, as some Nazi apologists would claim - an immediate one, but given another 3-4 years, it's hard to believe that conflict wouldn't have broken out anyway, and over that time, the Soviet strength relative to that of Germany would only have grown. Even without his personal dislike of Communism, Hitler had little choice but to strike when he did, lest he lose everything. In hindsight, invading the SU was a long shot. But frankly, not invading them would've been every bit as bad from the point of view of the long term goals of Naziism.