Real question, why isin't it? Could put it under feral sense with default being on, but the user can choose to turn it off if they want, I personally feel its one of the dumbest features added to the game, same for the forward staggering zombies do which makes no damn sense. I know i'd turn it off for sure, as its a stupid cheapshot feature and nothing more. Yes, I am aware mods can disable it, but thats no reason why it cannot be a ingame toggleable option when stuff like day/night/bloodmoon zombie move speed and feral sense is. Please add it as a toggleable option instead of forcing us to use a mod to do it.
By rage I don't mean where they hit random blocks after fall damage, I mean the one where after you hit them they randomly start running at you at mach 2 speed just out of no where.
While your at it maybe add digging zombies with 3 choices as well: All, Animals Only, or None can dig.