OP, I understand your frustration. It's really sad, vile, stupid behavior. It really is and I dont know what IQ one must have to enjoy "playing" that way.
But, every freaking on line game has its good share of these morons!! And since you -or anyone else- can't control their actions, the only thing left is to adjust your reaction to that fact.
This behavior is not news at all for anybody here, like it or not. You knew, better probably than your friend, that an attack of that kind was perfectly within the realm of possible outcomes in that situation, and yet, you decide to get disgusted because it happened?
Sucks. I know. I got killed myself on my maiden fly. Did I get mad? Not really: I had been reading the forums for over a week by the time I get to play. So, I knew I was at risk as soon as I launched.
Finally, being a game, are you really gonna get that mad about it? Those poor people in Nepal are having a hellish of a time right now, to put things in perspective, but here we are giving importance to these trivial things.
I just hope you and your friend take it lightly and just move on. The world is unfortunately full of morons. It's your decision to let them drive your emotions and spoil your fun! Keep playing in open and in no time, you will find 10 cmdrs that are worth the experience instead of that stupid one.