Have you ever been shelled? Or fired upon by a member of an enemy army who's trying his level best to kill you?
I have. It's not an experience I'm anxious to repeat. I think you're drastically under-estimating the average person's aversion to physical violence and the lengths the vast majority of people will go through to avoid ever being in proximity to it.
Successful rebellions start with demonstrations and build. The escalation of protest and response is necessary to build the kind of commitment a sustainable campaign of violence will require. You can't just conjure a willingness to run into gunfire for people who haven't been trained to do so, and thinking that you can just jump past the slow brewing of rage you need in the general population is idealist at best and naive at worst.