Considering fear of Bolshevism also caused fascist dictatorships to spring up in Italy and Spain among other places let's put the blame on Czar Nicholas II then for ignoring the warning signs! That Dummy should have listened to the Duma. :-)
World War II started because of a lot of tragic coincidences, any one of a thousand events, had they gone the other way, could have avoided the war. Imagine if only someone had bought some of Hitler's paintings when he was in Vienna.
It started when the wife of a customs agent gave birth to a son, in Braunau Austria, near the end of the 19th century.