Honestly the use by American racists of 'Anglo Saxon' as a euphemism strikes me as clear an example of 'cultural appropriation' as one could ever dream of having the misfortune to find. Please leave us and our history alone and make up your own damned terms.
I agree on principle and think these guys are POS, but White Americans are Europeans - some are English. For the best of everyone (newer immigrants, most of all), I believe it’s important we remember that and don’t further the creation of an “American” “ethnicity” that implies European catch-all descent.