The implication that there is or has ever been a monolithic "white culture" is idiotic. It is one of those assertions where the left and right horseshoe towards falsehood and depravity. That is to say both the Klan and extreme progressives agree there is a magic all encompassing definition of "whiteness".

This concept itself is racist because it assumes Ashkenazi Jewish, Nordic, Russian, and Irish cultures are identical in some way, when they obviously aren't. "The shared amount of relative pigmentation in skin" doesn't culturally unite people, nor does it account for their shared values and traditions, or lack thereof.