Umm, these folks aren't Mennonites or Brethren, no matter what they say.
There is a huge difference between actively fighting against the country you live in, vs. yourself, personally, deciding not to use force.
The difference is that between someone who chooses not to become a Marine, vs. someone going out and spitting on Marines.
I'm curious, could you explain how they are 'actively fighting' against the country they live in?