Strength Effect does not apply to Iron Golem

{*}{*}I was using the potions and command of "strength",when I noticed that the Iron Golem didn't have its damage increased by the Strength Effect (nor by the Weakness), this is quite strange since everyone receives this effect(I noticed when I put him against the Warden,and put the Health Bar on him, that it went down by the same amount with or without strength effect on Iron Golem).