Except that the system allows for another player to hit me from dead 6 and fly away with no damage.
He doesn't hit you on his screen, thus no damage.
And this works actually both ways, with HIM hitting you on his screen, taking damage while you don't. But that's most often conveniently ignored in this kind of threads.
From the P-47 pilot's film: The P-51 (Lusche) runs
intentionally into him on the Pony pilot's FE - "lusche has collided with you". Only the P-51 takes damage
The problem is, folks tend to notice this effect only when it's them who get the damage. If you would do a survey, it would turn out everybody is "losing collisions" almost all of the time