I wonder if any Atheist Identity Survivalist groups exist?
Some of the people in those groups are a little nutty sure- all groups contain a number of nuts. I'd feel much more safe meandering around in the wilderness of the NW than a ghetto in New Orleans though due to the murder rates.
From my experience, the christian militia type people prefer to stick to themselves and shun those who don't follow in step with their ideology. Over the past few decades a handful of incidents have been caused by people in their circles which is far less than others.