(via DenBeste.nu) Robin Goodfellow has this fascinating article on the roots of European Post Modernism. 

At the core, he (she?) argues it is caused by the Post-Colonial experience Europe collectively experienced:

Over a period of several centuries (most prominently from the 18th through the 20th) many nation-states in Europe constructed and operated vast world spanning empires. At the height of Empire building the majority of the population and landmass of the world were under the control of a small handful of Imperial nations. Despite centuries of buildup, during the 20th century those empires collapsed very rapidly in only a few decades, dramatically changing the geopolitical structure of the world. From that catastrophe Europeans took away very potent lessons in empire, culture, and politics. Unfortunately, they were very much the wrong lessons.

...Europe came away from imperial collapse humiliated, shrunken, traumatized, and chastened. Fueled by such feelings, post modern and cultural relativist ideology profited greatly in Europe. In many ways the retreat from empire was the "vietnam" event of Europe.

A critical second observation which we see reflected by faith in technocracy today is the separation of "elite" and "mass" culture in Europe:

...whereas American culture has been for a very long time primarily mass culture, the same is not so in much of Europe, such as France, where the elite had (and have) much greater influence and power. All the notions that the Imperialists held dear (such as market capitalism, industrial development, the forcible spread of "civilization", cultural assimilation, the superiority of the white race and the Christian religion) became denigrated and vilified. It was quite right to vilify many of those ideas, either in whole or in part, and that rightness reinforced the presumed rightness of the vilification of the total package.

So, now we've got a bunch of nouveau, self-styled Elites who have a lot more time on their hands (cuz they aren't running an empire) AND no longer feel like they are the center of the world:

Faced with the collapse of Imperialism, the failures of old world governments and diplomacy, and the rise of Russia and the US as superpowers (whom the Europeans perceived as less sophisticated and less cultured) the European elite reformulated new strategies of moral superiority and sophistication.

Unfortunately, the homeland(s) of Locke, Smith, von Mises, the Greek Democrats and the Roman Republicans also lost their Moral centers.    Even worse, they sought to create a intellectual system with no moral center where individuals with obviously amoral policies were simply "people of different perspective":

..Brown tyrants for brown peoples was a perfectly acceptable situation in the neo-realpolitik of multiculturalism. Not only that but the idea of western governments passing judgment on such "brown tyrannies" reeked of Imperialist cultural superiority and was consequently unacceptable. Thus, western nations have no moral standing from which to judge the actions of non-western nations. These ideas were extended to embrace the notions of "might makes wrong" and "weakness makes right".

I'm not well versed enough on the recent cultural/intellectual history of W. Europe to spar with Robin but the case laid out holds water.