One of the issues I see is that half of the country seems to see Oath Keepers and Threepers as “extremist militias”, while the other half sees them as a reasonable reaction to an increasingly powerful government.

I’m explicitly not taking a position on this topic -instead, I want to call out the significant disparity in perspective. HN seems to nearly unanimously accept the labels applied to these groups without question while other communities of which I’m part reject them (also without question).

More worrying than the polarization to me is the fact that neither group seems aware that other sees things so differently, and that the opposite opinion is broadly held by the other side. The assumption seems to be that only “extremists” would hold that view, when the reality is that 30%+ of the population share it.

The “moderate” position is vanishingly small these days.

What does a "moderate" position look like when it comes to white supremacy?

This is exactly what I mean. Which specific group are you referring to?

Using “extremist”, “anti-government”, “right-wing”, and “white supremacist” almost interchangeably seems to be very common. Both this article and the report its based on repeatedly refer to “white supremacist or far-right militant groups”. Those are very different things.

It’s infiltration because they’re doing it to further their aims by subverting those* of organisations they’re joining. The Internet means that planning and radicalisation can happen without ever being explicitly targeted by organised extremists. Hence self-infiltration much like the Islamist terror attacks carried out by self-radicalised people.

* - Nominally at least.

Yeah, there were many Klan members in the police force back in the day? This article seems to suggest it's a new problem