Indeed. It's not like every self-styled "militia group" was present at the U.S. Capitol on Jan. 6. In fact, most of them weren't.
But a lot of the largest and most high-profile ones were (Proud Boys, Oath Keepers, 3%ers, etc.). A lot of that militia subculture very consciously sees themselves as defenders against internal enemies.
And why wouldn't they? The U.S. is not going to be invaded any time soon. The idea that the British could sail in at any moment and sack Washington, D.C. like during the War of 1812 just isn't true anymore. There are no more bands of armed Native Americans on horseback roaming the American West.
Without a real target, it seems like militia groups turn their sights on other Americans, and that's what concerns me.