Johnson has a right to be upset here, both players were given 5's for fighting as they should've been, but the instigator penalty is part of the game to prevent a player from jumping an unsuspecting opponent. Johnson asked Cuylle to fight, he said yes, they dropped their gloves at the same time. That's not an instigator.
We've seen this call go both ways more than once and it seems to be a judgement call made by the officials, if officials can bend and change the rules as they see fit, what're we even doing here.