Qué es la historia

I think this is wrong. The main lessons or most valid observations about WWII have nothing to do with National Socialism at all. There are however, two sets of "textbooks" for the period both of which are based on enormous self-serving distortions. Textbook I prevailed before the establishment of what Finkelstein called the "holocaust industry" in the mid-1970s (coincidentally at the same time the US was losing in Vietnam but fighting to stop decolonialisation everywhere else). The textbook I version was that Nazism, Communism, and Fascism were all the same and the only decent, freedom-loving system was "pure Anglo-American capitalism". According to this Germany, Italy and the Soviet Union were all evil because they did not follow the Anglo-American lead established at the end of WWI (with the US as regent for the bankrupt British Empire). Almost all the major leaders in Britain and the US had nothing but admiration for the NSDAP viewing it more or less in the same way Pinochet or Franco were viewed. Then Hitler stepped out of line and tried to put Germany in front. That is why Germany was thoroughly destroyed the second time. Japan was a more purely US enemy than Germany-- abetted no doubt by US racism (the US has always been more vicious toward Asians and its own African-Americans than toward Jews).
By the time the US had lost the Vietnam War the "holocaust industry" was a high-growth sector. This is the origin of the Textbook II version which attempts to tell the entire story of 1932-1945 as if it were a newly discovered volume of scripture to supplement the Pentatuch. Now WWII was to be interpreted as the crusade against the great crimes against the Jews in Germany and to a lesser extent those in Eastern Europe (although it was clearly Eastern Europeans- Jewish and Gentile who bore the highest proportion of death in the camps and not Jews per se. (This does not negate the crime or the loss of life-- but puts it in perspective.) The "holocaust industry" does not pay any attention to the mass murder of Russians, Poles or any other group because it is not concerned with a history of the real events or even the way the events were seen at the time. Goldhagen's research was not only sophomoric but littered with sloppy and even negligent "scholarship" and therefore is not worth the time it takes to read. If his father had not been an important Harvard personality the dissertation probably would have gotten no serious attention at all.
The great struggle of the 20th century was and continues to be the struggle against colonialism. The Great War was in part motivated by British greed for the oil in Ottoman-held Mesopotamia. HM government was willing to slaughter some 50,000 men on the Somme, not to mention elsewhere to make sure that Anglo-Persian oil was secure in British hands. This they accomplished-- being forced to share it with the US after WWII.
Every major war and state-sponsored mass murder in the 20th century has been driven by this colonialism and its successors. This struggle is not over. During the Second World War several million Jews and other  people in the territories occupied or under siege by the German Empire were killed in a war which was essentially colonial. It is no accident that the so-called "death camps" were all in territories that Germany had conquered or occupied. This is typical of colonial war as it was practised in Africa, North and Central America and Asia. 
The fundamental story of the 20th century is the viciousness with which the Western powers were prepared to sacrifice millions of lives to expand or maintain these sources of "free labour and raw materials". The positive story of the 20th century is that despite this viciousness and the deaths of millions the people of the colonies have continued to regroup and resist-- even against forces of overwhelming superiority. Those who view this period with bitterness and sarcasm-- and I am not one of them-- could say with some justification that the only group of people in the world to be allowed to create a national colony of their own after WWII at the expense of everyone in the region-- were Europeans who decided that their claim to a monopoly on Jewish culture and identity entitled them to take and hold land by force in the region their allies seized from Ottoman rule at the end of the Great War. Of course this could not be done without a new myth. This new myth was another version of the story that Europeans were the only people capable of making land fruitful and a country profitable. This myth was shared by the Europeans who colonised the region whether they claimed to be Jewish or Christian. In the so-called Middle Ages the Roman pope summoned Christian princes to seize this land for virtually the same reason. But so much has been forgotten since then that the old story has been dusted off to justify what is nothing more than another vile chapter in the history of European colonialism. 
This chapter will no doubt also take its place in the history books-- but we do not know in what kind of world that will happen. Long after the Second World War was over, human rights were deemed subversive in countries that now belong to the European Union. It would be absurd to say that this was only an afterthought. WWII was not a war for human rights. Human rights was a demand forced on the victors and in many cases used as a baton to beat the vanquished. We can indeed be thankful that the anti-colonial movement forced this issue. It was the war against colonial rule in Africa that forced Portugal to overthrow its dictatorship. The lesson from WWII is really that no one can be really free as long as there are still slaves. This is a lesson that has no religious or culturally exclusive value. No country is entitled to claim its "freedom and peace" at the expense of another. But this lesson has not been learned yet-- as immediate history shows us time and again.
Mit freundlichen Grüßen/ Cordialement/ Cordiali saluti/ Yours sincerely/ 
Dr. Patrick Wilkinson
Institute for Advanced Cultural Studies - Europe
Kirchstrasse 32
D-40227 Düsseldorf