Wow! this is a LONG thread. Since the fire is burning so nicely, more fuel certainly won't hurt. The debate goes back to the very early AW days and hasn't changed in its basic character since day one. There are adherents to one way or another but the question has no definitive answer.
This "game" has no rules. If you doubt me, you can quote from the official AH rule book. Oh, there isn't one.

There is actually no way to create a set of rules that will spell out in black and white what would be allowable behavior in a way that cannot be interpreted differently at different times. The closest analogy I can think of is trying to play traffic cop at the Indy 500. Everyone there is trying to go as fast as they can, and how they go fast is immaterial as long as they don't physically endanger anyone.
Here there is no physical endangerment to consider and the object is to kill enemies. Trying to split philosophical hairs into smaller and smaller fragments may be amusing but ultimately futile.
The picker is the equivalent to an infantry sniper. At long distance and relatively low risk to himself, he kills. Dead is dead and there is no other way to term it. The kill is just as dead whether it was picked or it happened in an intense furball.
So for myself, and this is for myself only, this is how it breaks down.
1. All red planes are targets and should be shot.
2. There is no such thing as an even fight between two people, EVER. Trying to make is so is a waste of time and effort. The only even fight is against yourself and we call this schizophrenia

.
3. The object is to get kills and not be killed. (If you like getting killed, check into a clinic

. If you are setting up your fights to have an equal chance of being killed, hmm, do you see a problem in this?

)
4. A kill is a kill is a kill. There are no bad kills.
5. There is no inherently "nobler" way to get a kill. Thinking so creates frustration.
6. If you want a duel, go to the dueling arena, that's why it exists.
7. If you lose, suck it up and learn from it.
The only sins are:
1. Acting like a jerk.
2. Whining on 200 or PMing about how you would have won if only the killer didn't do X. It is NOT a matter whether the amount and intensity of the whine will undo history and make you not dead.
3. Talking in one way and acting in another so that the poor SOBs who listen to you become better kill fodder. This is disingenuous and makes you look like a jerk.
To that end, I don't listen to 200. In my opinion it is mostly a terrible waste of bandwidth.
On the other hand, I think Corky is absolutely right. The class with which you treat people in this competition is the measure of you as a person. Those without class won't get this (hence their problem). People will remember the class long after the kill is forgotten.