I again say Versailles was the main reason for Hitler because of being too harsh. And again I´m not a nationalist. I only argue with the Germans point of view in the 20s and not today. If you want to understand history, you must understand the poeple in the time you want to see.
I think the Versailles-treaty can't be looked at without looking at it's backround. And it's backround is a mess of European and international geo- and powerpolitics and nationalism and domestic-issues of that time and lots of other dynamics which come into play. Recently I've read history of Europe written by a British guy, which noted, that the British 1871 where to caught up with other issues, that they failed to see the poblems caused by a new born nation, dwarfing any other on the continent, including the UK and omitted to interfere with the founding of Germany, making it a little bit smaller. And the power-void a declining Austrian-Empire, would leave open, which would be sadly missed, when a few years later, things would have to be "balanced-out" (the need for an ally versus the Russians, brought Austria close to Germany).
And one of the main problems with the raise of Hitler was, I must confess, that was a reflexion which I got taught in school, the mithology of a "Germany which had to be unified" and the way Bavarians, Frisians, Hessians, Saxons and all the rest got taught that they are "Germans" now, and their old nationality would be meaningless. The way it was taught, and the hard times in which Germany fell later, where a dangerous brew. And the knowledge of the Germans, that the really were the dominating military power of Europe (except for Russia, but which was tied down with its on problems and the resulting incapality to really matter in that time period) made for one the "backstabbing"-legend so plausible, the cutting off of many its land so "hurting" and "humilating" and the "unfairness" of obviously "weaker" countries having a bigger share of the pie. They would be much harder hit after WW2, which so the near complete destruction of the diversity of central-Europe with its language patchwork (which was not bad in itself) swept away by nationalism and is only remembered by the architecture which survived and history books.
And I think the Versailles-treaty had a huge aspect of trying to contain the Germans, while power-politics started to interfere.
Think how many people take the "alliance" between USA/UK/France easily for granted. Or now the infamous "British/US" alliance with the "special relationship". When taking such things for granted and look back in history, one might get a distorted picture. I don't claim my view is correct, but the huge writings about this all and different views that exist on the way the first great war ended, shows how complex it is.
And then this "Elsace-Lorraine" belongs to me, no me, no me. Elsace-Lorraine belongs to Elsace-Lorraine. If history would have been slightly different, there would be a country Elsace-Lorraine, as there are Belgium and the Netherlands today. One should not forget, that Belgium once was dissolved and swallowed by another country too. But by another country not about 20 or 30 times bigger in size. Obviously, Elsace is happy now where it is.
And to the war-guilt. All those bigger European nations where like a pack of hungry wolves, which couldn't wait to get on eachothers throat. The war had to happen, no country had more guilt then the other