Christopher Hitchens wrote an article on the topic for Slate on May 18, 2011. You can check it out on http://www.slate.com/id/2294965/. The following three extracts will give you an idea of it.
Why is it that we cannot read any discussion of a political sex scandal, or a sex scandal involving a politician, without pseudo-sophisticated comments about the supposedly different morals of Americans and Europeans? And why is it that this goes double if the politician is French, or if the reactions being quoted are from Gallic sources? And when did this annoying journalistic habit become so prevalent? It must have sprung up quite recently, or at least since the time when Charles de Gaulle and John F. Kennedy were presidents of their respective countries.
A related problem derives from the belief that Americans will not tolerate marital infidelity from their politicians.
Much hypocrisy is, of course, involved in both reactions. But of the two, the display of the Gallic “shocked—shocked” reflex is by far the least “adult.”