What self-deluding French reactionaries might think is irrelevant. France circa 1100 AD, or 1700 for that matter, is meaningless. Or no more meaningful than various European pasts are to America in the sense that any given period came out of what preceded it, and given that America is largely a Western culture it is a product of these pasts. Any appeal to 'tradition' by conservatives is about the present, the 'traditions' which are being invoked are at best arbitrarily chosen and reinterpreted for the present, at worst made up of whole cloth. To the extent that conservatism is authentic it is seeking to preserve the existing or to return to a recent past. Even the latter isn't quite that simple - nostalgia for the nineteen fifties is already in part a nostalgia for a specific contemporary re-imagining of the fifties. When you go back centuries seeing anything authentically 'traditional' about those 'traditions' is ridiculous.

This was a hot topic in the eighties and nineties. The closest that any of it came to your viewpoint was Anthony Smith, e.g. The Ethnic Origins of Nations. And even Smith wouldn't go anywhere near as far as you. The more widely accepted interpretation was that set out by Benedict Anderson in Imagined Communities or the modernization one in Ernest Gellner's Nations and Nationalism . On the 'authentic' traditions Eric Hobsbawm (ed) The Invention of Tradition is fun.

Germany had only a couple of decades in which it was involved in conquest of foreign lands, whereas Britain's imperial career, based on military might, spans centuries.
Germany as a state didn't exist all that long; it's sort of hard for a non-existent state to be conquering people. France, Spain, Britain, and Russia on the other hand... or even the Dutch. Of course if you look at the Prussian and Habsburg states a rather different picture emerges. Polish nationalist versions of your view of authenticity and tradition see the early Prussian Teutonic Knights based state as an earlier version of Nazi Germany with the Deutsche Orden as the first draft of the SS.  Amusingly enough so did the Nazis. In the Polish communist nationalist remix this became class struggle with Germans as the eternal opressing imperial nation-class.  Wilhelmine conservatives saw that state as the early incarnation of their own vision of Germany, Drang nach Osten included, what a surprise. All that shows is that people can and do play any game they want with  ancient 'traditions' in order to find support for whatever political interpretation of the present they're pushing.