"You would call [groups from a time when white supremacy was widespread and socially acceptable] white supremacist today" is not the gotcha you seem to think it is.
> look at how the FBI treated [white supremacist] labor groups versus fascists ones in the 20s [..] no need to worry about the decades after, they killed enough [white supremacist?] leaders to stop [white supremacist??] leftwing voices in the US
So the fact that the labor groups the FBI targeted were white supremacist by today's standards makes those sentences complete nonsense.