Of interest on this topic,
here is a DARPA document reported on by Politico about "extremism" in the military.
Had a look at this, instead of speculation lets look at the source material.
The political axe grinding involved is clearly visible. And not merely in what is listed there... (a lot of leeway and reality stretching was involved into getting the patriot extremism point there, but you could see some rationale behind it, though the latter minor anti-feminism entry is a joke, and built around a confused mix of 4chan and PUA slang.)
But now when we see the above setting the low bar to entry to list of domestic extremist ideologies threatening US military and civilian government, what is truly damning is what is *not* on that list.
First off and most obvious, these clowns have managed to put in a religious extremism entry (correctly), and in it they have managed to mention Christianity by name (very dodgy), through use of clever wording, while not giving the same favor to a certain other Abrahamic religion who clearly provides a much greater and obvious threat in that regard, see: Nidal Hassan case.
Then they manage to include Ethnic/Racial supremacy (kinda correctly) but only list more or less supremacist (technically they shouldn't with the latter) organizations favoring white/western societies, while failing to give even one honorable mention to any non-white supremacist group by name, not even those who recently were associated with terrorism, like Black Hebrew Israelites or New Black Panther Party - instead they only mention those as a generic, and ascribing the "vast majority" of such extremism to the white associated groups.
And last but not least, they have managed to limit the mention of any far left extremism to anarchists who are "opposed to government in all forms".
Ok, but where are all the communists, marxists, radical socialists, and variations of them who all want a powerful, all encompassing government forcing everyone to build socialism whether they like it or not?
Do they not exist, are they considered not extreme enough, or do they not constitute a threat to US government or military personnel? Consider these questions in light of the low bar presented in the cases they did put there.
And from the other side of the aisle, the Greens are going to feel betrayed through their extremists being put on the list, and also the not-an-organization Antifa, will not be happy both being listed there, and to add insult to injury, under "anarchists", even though a whole lot of their activists are clearly not "opposed to government in all forms" anarchists, but different kinds of far left extremists.