Regarding the "oath keepers" constitutionalist militias etc
There's a spectrum of populist thought, running from authoritarian, all the way to libertarian and even a few anarchists.
It's important to know which part of that spectrum you've got stood in front of you,. Whether it's the coercive authoritarian variety, or a more libertarian strain.
Just as Noam Chomsky (left anarchist) can hardly be compared to the authoritarian end of socialism Stalin, Mao or Pol Pot
Or Ron Paul (capitalist who believes in an absolutely minimum state) can't be compared to - ok, that's difficult, because most of the authoritarians turn out to be socialist of some sort when they're examined closely - so I'll say Rockefeller
A bunch of the constitutionalists and militia types are actually their own flavour of libertarian, and can't be realistically compared to the authoritarian representatives of populism (KKK, Aryan nation...) Despite the conflation that appears from the likes of the SPLC, and gets gleefully spread around.
There's a good explanation and examination of the libertarian wings of capitalism, socialism and populism in an essay by Roderick Long (he' prof of philosophy at Auburn, and I think currently identifies as a left / bleeding heart libertarian anarchist)
Well worth a look, even if you're not a libertarian of any variety
http://praxeology.net/libclass-theory-part-1.pdf
http://praxeology.net/libclass-theory-part-2.pdf