Bias against the Germanic or Anglo-Saxon roots of the English and American order

Thomas Jefferson mainly wanted to see a renaissance of Anglo-Saxon institutions in America, with such things as the separation of powers, which was the real bases of English freedom---Jefferson was not primarily representing the Enlightenment ideas of Locke and Rousseau. Why is this fact, which can be backed by good scholarship (see "The German Roots of American Order,” by E. Christian Kopff, Modern Age, Fall 2015) not better known?

I think modern liberal and neoconservative intellectuals (and even many real conservatives) do not admit that human nature is at root biased toward kin and ethnic group, although some of them, like Leo Strauss, promote their own group, however subtlety, over other groups, even while claiming to speak the “universal” truth in promoting an “American creed” or a “propositional nation” of universal "reason," which is in fact biased against the Germanic or Anglo-Saxon roots of the American order.

The intellectual abstractions of Plato, the French Revolution, and Leo Strauss deny or block the more important real conservative fact that political institutions grow from customs, conventions and the ethnic history of a people (and I would emphasize the genetic traits) cultivated over many generations. Ideas are of course important, but distinctive people create distinctive cultures.

Is it the lack of courage to admit the truth of natural bias toward ones group in human nature? Is it ignorance? Is it fear of being called a "racist?" Is it deception? It is a serious problem and a big pain in the neck at any rate, and I'm pleased it is being talked about, however underground.