King has invisible speed. He would hit him. Law doesn't have Zoro speed or reflexes.
Who cares if Law can pierce King's body he still can't cause him any damage. King can survive concussion attacks without any damage.
King can damage Queen, stop the BS. Queen was bitching because King attack hurt him.
That's why King said he wished it was Queen's neck. That statement would have been pointless if his attack didn't cause Queen damage.