Because we never officially see Scorpion stabbed AND killed by Sub-Zero, putting that into the character relationships is just speculation. Personally, I think he did. Several characters appear to have been killed by another, but we never officially see it, therefore we're speculating. The only people we ever see officially killed are Li Mei by Hotaru, Sheeva by Kenshi, Kenshi by Shang Tsung, and eventually in MK 2011 Raiden is killed by Shao Kahn.
Since we can only speculate on who killed who, we need to stop putting in "Killed by Baraka in Armageddon" or "Killed Scorpion in Armageddon" because while it appears like it, we don't ACTUALLY know that. For example, Baraka's head. Kung Lao could have been throwing his hat at Shinnok's Clone when he deflected it into Baraka's dead corpse, which may have been killed already. Someone could have picked up Baraka's left arm and stabbed Sub-Zero. We don't know what happened, therefore we can't say with 100% certainty who killed who unless we actually saw it. If there are any other people you KNOW were killed because you saw it in the Battle of Armageddon video that I missed, feel free to post it. Otherwise, I'm simply adding the "beliefs" in the trivia as many believe so and so killed so and so.