This thread won't end until a developer proves him wrong, by the looks of it. So far he has basically ignored every explanation given to him like.

Here's proof that damage has to stack based on the games mechanics: the game runs in frames, and for the processing of information, there is no shorter increment than 1 frame. The game cannot determine when a hit is happening, it just detects damage to joints. If there was no system of damage stacking, the damage a joint has taken would be reset to 0 every frame. Most hits start making the joint red atleast 2 or 3 frames before the dismember actually happens, making the damage in those 2 or 3 frames of that one hit stack together in order to achieve a dm.

The joints are slowly getting red 1 frame before the dismemberment happens (If you watch the replay with x0.01 speed), but not 2-3.