There were abuses by bankers and capitalists, many of whom were Jewish. There were "Jewish Bolsheviks." And there was resistance and terrorism. As for the war being a prerequisite for the Holocaust, see the intentionalist vs. functionalist debate.

The avoidability of the war is a more subtle question. Along with Orwell, I think war was inevitable and obvious by 1936, at least if we consider the conquest by Germany of continental Europe possibly excepting France, Switzerland, Belgium, and other fascist powers unacceptable. Even then, the war might have been confined. I see little historical necessity for e.g. the alliance of Japan and Germany or the attack on Pearl Harbor. At what date would you agree the war was avoidable? 1918? 1930? If you'd like me to find particular historians - I'm not including Pat Buchanan - I will do that. But there's a pretty wide range of opinion here. (Aside: I'd like to find resources that framed the question primarily in terms of German-Soviet relations instead of Anglo-Polish ones.)