Martin Atkinson clearly saw that De Gea was on the ground with his back to play before Smith Rowe took his shot. He moved his whistle to his mouth but opted not to blow it until after the ball went in the net (when there was actually no need to blow it all) presumably in line with the wait-and-see VAR protocols. We are told time and again that player safety must be our number one priority. Martin Atkinson had had no chance to assess how serious the injury was. On a safety-first principle he should have stopped play immediately. Safety must override VAR protocols.
Now, consider a slightly different scenario. If De Gea had been seriously injured, or at least pretended to be, and was immediately substituted, would VAR have decided that Martin Atkinson was wrong to have allowed play to continue and that the goal should be disallowed? And if not, what is the point in waiting to blow the whistle until the ball is in the net?
From what I understand of the incident, it doesn't sound like the safety principle would apply too much here as it sounds there was no case to think it was a head injury and presumably if it had been an outfield player in midfield no one would complain about play continuing in a similar incident.
If there was a serious injury then hopefully the referee would stop the game straight away and the VAR protocol of wait and see obviously wouldn't apply because there'd be nothing to wait for.
In general, my instincts are that an injury to a goalkeeper or a defending player who plays all attackers onside should be treated a bit differently because of the tactical advantage it can lead to for the opposition. It doesn't quite seem in the spirit of the game for a result simply because the goalkeeper wasn't able to stand up to save a simple shot for instance. But obviously the referee needs to have time to assess this and you don't want to create the precedent of defending players feigning injury simply to stop the game. An incident where a goal would have resulted anyway is also a bit different.
NB Obviously the above doesn't apply to serious injuries, in which case the game should be stopped immediately, regardless of who and where.
Does anyone remember the incident where Rob Green got injured for the England B team and missed the 2006 World Cup? He got a serious injury whilst taking a goal kick and the opposition striker got the ball and had an open net to score. As a referee, would people stop play immediately or allow the goal to be scored? It seemed a bit unfair on Green that he had no chance of making a save as he was lying on the floor injured but on the other hand the opposition would have had a 1 on 1 anyway so a strong chance of scoring without the injury.
If De Gea had been seriously injured and Atkinson had failed to stop play then I presume the goal would have been allowed as there'd be no obvious justification for disallowing it. Does the referee absolutely have to blow the whistle before the ball hits the net or could they argue they'd made the decision to stop the game already but not managed to blow the whistle in time? Obviously if a referee penalises a foul it doesn't matter if the whistle goes after as their original decision takes precedence but I suppose it is different here as no offence as such has been committed. 0