I may regret this, but I will weigh in here. My opinion is probably low and of little value BUT.....
Over the years, I have encountered many "HO" experiences. I will admit there have been several where I did not make any effort to divert... even when it was too late. However, in recent years, I have found it more fun to to high or low in an effort to try and make A2A combat more fun and worthwhile. HOWEVER, I have seen where, due to no fault of the other player, I haven't gotten the message "so-and-so has collided with you" even when I've tried to go high or low before we got too close.
I almost have to assume that if you go into a H2H situation that a HO collision is inevitable, and its a gamble and toss up as to "who" will be at "fault".
Too many times I've seen HO collisions with myself where the aircraft coming at me seemed not even to be close to impact but off to one side or another. I've kind of assumed it is just part of the game...
So, if, by chance, you BOTH turn HO, I would suggest that both parties are at fault. I understand the game doesn't score it that way, but I already assume that premise. If someone turns into you and you are not turning, they are going to ram you (front or rear), that's a whole different story.
Again, my opinion may have little weight in this respect, but this is how I kind of view it.
Remember, this is a game, not real life. In a game, you crash or land only to go again. Live and let live, let the proctors of the game decide blame and dish out any consequences. It does no one any good to shout, hound, berate or become enraged at someone else's mistake or intentional "misguided" intentions. Leave it to someone else, continue to be the better person with your head held high and enjoy the game. Its a game, nothing else.