Me.and madman weren't friends contrary to popular belief we were in a faction together for a month or 2. I had no loyalties to him.
Well I guess that depends on your definition of friend, I had helped you out in many ways I wouldn't have for a stranger, and you had loyalties to me in the sense we were in the same faction and regularly working together over a period of several months.
I had even been to your main bases repeatedly, something I thought was common with groups who trusted eachother enough to do it for timesaving purposes.
Then you backstabbed me the first chance you got for gear I had spent a significant period of time acquiring. (that we were in the process of trading)
So yeah, fair game is fair game I guess, but I wouldn't give you an inch of trust in the future beyond not shooting you if you are in the same faction, and you earned that.