Not just one of the most cruel and criminal actions in history, it was also the dumbest decision Hitler made in the course of the war. This moron thought he could fight the whole world and stand a chance of winning. And Stalin for his part was rather naive as well, by assuming Hitler would keep his word from the 1939 treaty, even when the warning signs were there. He also reacted slowly and caused more Soviet deaths.
Hitler easily tops the list of most evil in history of the world. However painting him as a moron at least for earlier decisions, arguably is part of the Clean Wehrmact myth with memoirs written by Nazi generals such as Guderian/Halder who didn't understand the strategic thinking of Hitler's desires for oil. After they survived they did tried to paint Hitler also as incompetent to show how they "opposed" him.Later on by say 1944 and 1945 Hitler did go borderline half insane but early on some of his most evil decisions actually had a degree of strategic thinking.
It is true, allot of the surviving generals liked to pass off their loss as being do to Hitler’s meddling, which wasn’t that common and, in the early to mid war, not always wrong.
But, it’s hard to say that invading the USSR in the first place wasn’t titanically stupid. The thing of course being that virtually all the Wehrmacht officer corps, excepting the quartermaster’s office who pretty much gamed out exactly what was going to happen, was completely on board.
