Great summary of two of the world's greatest tyranical regimes. However, I want to add two points of my own here.
Hitler's hatred of Jews and Communists
One of the things that is often overlooked in the between-war history is that Munich and parts of the surronding countryside was taken over and turned into a Soviet Socialist Republic for about a month in the fall of '22 or '23, until it was broken up by police and the German army. Of the seven ringleaders - none of whom were captured and tried for this event - five were Jewish. It is quite possible that this event helped to cement Hitler's hatred of both Jews and Communists.
"The Jews rule the world/Zionist conspiracy" notions
Most of Hitler's hatred towards Jews was enhanced by Europe's anti-semantic attitude, fueled by a percieved notion that Jews were the ones who controled the money flow and kept that to themselves. (The whole notion as mentioned as to how Jews were percieved as 'shrewd businessmen'.)
It is quite ironic that one of the reason why Jews were running so many of the banks and businesses of the time - or so it was percieved - may very well have its roots in Mideaval Europe. At the time that commerce and mercantile guilds were coming into their own, it was believed that a Good Christian Man could not handle money and still be a Good Christian Man. This was based mostly on the story of Jesus chasing the monylenders from the Temple, and the mis-quoting of the old saw "Money is the root of all evil." Jews, being seen as 'not of God' - which is ironic, seeing as the first Christians were Jews - we deemed as the only ones who could handle money. Thus, Jews became the money-lenders and then bankers.
That old saw is misquoted? Yes, the actual quote is "For the love of money is the root of all evil." This means that a Good Christian Man could still be a businessman as long as he spent a portion of his time making, as quoted by Dickens, 'mankind his business'.
Personally, I see as the whole of the 20th Century, stretching from the dieing decades of the 19th Century and spreading into the 21st Century, as one constantly lurching from one ideological extreme to the other. This, IMO, is partially what led to some of the regimes mentioned that emerged in the latter half of the 20th Century.
