I'm not sure if you're saying that that fight was an anomoly and was only stood up because lesnar is so big, but if you are, you're missing the point.
He was told the rules. He dropped Mir with a punch. He started flailing without any vestige of technique and hit the back of Mir's head. He was warned by Mazzagati. He continued to flail and hit him directly in the back of the several more times after the warning. The fight was then justifiably halted and stood up.
If you're saying that any fighter who repeatedly strikes the back of a fighter's head without any regard to their opponent's safety should have the fight halted and a point deducted, then you are correct.
If you're saying anything else, you're a fucking moron.