Oh sure, there are individual psychopaths out there who think InfoWars is documentary journalism, but the closest we have in the US to a group with a newsletter who would actually do something like that has membership in the dozens, not the thousands. Aryan Nation isn't posing as an alternative political apparatus. They don't send a guy to unclog your toilet or feed your elderly mother after you blow yourself up in downtown Spokane protesting affirmative action. They're not Hamas; they're not even the JDL. The hate the Gubbmint but they don't have A Plan.
The analogy to a group like Boko Haram or Hezbollah would be what if the Tea Party tried to shoot up the Capitol Building and start a coup d'etat. Those are the groups -- radicalized, violent, and also populous, multi-generational, and organized -- that I would worry about delivering a Suitcase from Allah or a Backpack from Jesus to Times Square.