Its not even close, David got caught but he would have got up and played on if he was looking the right way, there is a full thread of your own supporters saying as much over in the United forum. Coady was caught and genuinely hurt, Liverpool also didn't have to put the ball out they chose to. Had Salah scored it would have been a similar situation and no one would bat an eye. Not the same scenario at all. One was hurt, one wasn't the length of treatment and reactions after show the truth.
Liverpool stopped it not the ref.