Karnak, seriously?
Yes, seriously. Stop thinking of it in terms of traffic collisions and who is at fault. The program doesn't, and can't, care about any such things. All it knows is that on your front end two aircraft tried to occupy the same space, thus the collision. If two aircraft had tried to occupy the same space on your oponent's front end then he too would have had a collision.
Remember, unlike reality where a collision involved two objects, in AH we are talking about four objects. You on your front end, the image of your oponent on your front end, your opponent on his front end and your image on your opponent's front end. Due to the time it takes data to move across the internet those your oponent's position will never be the same on your front end as it is on his front end and likewise your position will never be the same on your front end as it is on his front end.
That is why collisions happen as they do in AH.
Specifically, in your example, your opponent had no way to avoid hitting you as you were not there to be hit on his front end, thus the responsibility to avoid the collision must be on you.