There was nothing wrong with Walker's reaction. He just showed disappointment that he didn't get the penalty.
Walker put his leg in front of Sterling. He's allowed to do that. If he's ahead in the chase, he is allowed to cut in front of the other player. Walker didn't do anything wrong there.
However, I can accept it wasn't a penalty, as Sterling didn't deliberately foul Walker, and in fact you could argue that by putting his leg in front of Sterling, Walker has actually tripped him.
The penalty incidents in the last minute though, had the referee looking directly at them. Dias was being held. That is clear, and that is a foul. There should be no "It wasn't enough of a hold" nonsense coming in to this. It is in plain language in the Laws of the Game: "A Direct free kick is awarded if a player... holds an opponent". If the referee chose to ignore this, VAR should have intervened. It isn't a subjective issue. Holding is a direct free kick or a penalty. Interpretation doesn't come in to it.
The handball seemed clear too. I've no idea what the current threshold is for handball. The laws say handball is when the ball touches the arm below the sleeve, which this certainly did. It also says it must be deliberate, which this may not have been, so you have to accept no penalty for handball, because whether it was deliberate or not is down to the interpretation of the referee.
So there were three penalty calls for City in the game. One could be said to be a stonewall penalty, two were debatable. None were given. When all these calls go on favour of the same team, it is fair to question the partiality of the referee and other officials.
