Seriously, I don't think this is that difficult of a subject.
There are weapons in a game to use, if you are killed by some metod which was put into the game to be used to kill people then I don't think you can complain (I'm refering to complaining about saber-throwing and guns mostly). However, if you, for some reason must take yourself out of the action for a few seconds or minutes, and it is obvious that the you have made an effort to remove yourslef from the action, I don't think that anyone has a right to kill you. Typekilling, afk killing, whatever, its just plain old ****ty playing. If you do it to me, whatever, but I know and you know that it was a kill that really means absolutely nothing regarding your skill, you might as well use cheat codes if you're looking for free kills like that. On the other hand, if you are sitting there, out of commission for a while, don't expect to be alive when you're ready to play again, and don't complain about it, because it is part of the game. In my experience, most really good players won't bother with a kill like that, so if you see that someone did that, go kick his ass.