All Ive heard for arguements for HOs is...
What you will get from me, and what I think is the best attitude about it, is to say that this game is primarily a GUNS game. As such when the path of a bullet from the barrel of my gun(s) intersects with the path of YOU then expect to be fired upon.
To me it is best to have the bad guy pointing away from me, but AH is a three dimensional environment and the geometry of movement being free on all three axis allows for unpredictable angles, which afterall makes playing the game such a fascinating undertaking.
Lastly, if your going to play the game with the attitude that a certain shot is not a sporting shot and should not be taken, then you are going to become upset because AH is not a sport. It is a combat game without restrictions. Get yourself in the path of my bullets you will be shot at. Having said that, of course, avoid the HO but be prepared to execute the head-on shot offensively and to avoid it defensively.
Shuffler, it is well and good to say
learn your aircraft but remember to talk about Situational Awareness as well. SA is just as important as understanding ACM and individual aircraft capabilites. If you cannot read the fight you are getting into then you are going to get hammered regardless of your abilities in any given aircraft.