I've heard these quickly become alt-right incubation machines. The "fellowship" becomes "brotherhood" and then you got a cult-militia going pretty easy after that.
There's no ignoring how the pictures can look externally. For example, I never imagined myself wearing a rucksack for fitness. In my experience though, the community is filled with men from all walks of life, political views, etc. I suppose like any group, its local membership is what most defines your experience. I've personally met lots of guys that I would have never met at church, work, etc because I worked out with them at F3.
Anyone whose political ideals include exclusion or destruction of classes of people may be "scary" to those classes, and in any case I am willing to be intolerant to people who have vocally, explicitly broken the social contract we all usually abide by.