I can support the Civil Rights Act of 1964 - an existing social structure - without being rightly defined as supporting white supremacy.
I can support woman's suffrage without being rightly defined as supporting white supremacy.
How do you distinguish between "taken as axiomatic" and "is the case"?
Eg, I can describe 1970s South Africa as being a white supremacist society, yes?
You certainly agree that at one point US laws were based on white supremacy, right? Eg, the Illinois Constitution of 1848, quoting https://en.wikisource.org/wiki/Illinois_Constitution_of_1848 :
> The general assembly shall, at its first session under the amended constitution, pass such laws as will effectually prohibit free persons of color from immigrating to and settling in this state;and to effectually prevent the owners of slaves from bringing them into this state for the purpose of setting them free.
That sounds pretty white-supremacy, yes?
If so, when did the US stop being a white supremacist society, and how?