I think they need to put out the rationale for making a decision like this one. Like US Football where the ref explains the ruling the fans deserve to know why a decision was made rather than the usual stonewall of silence. If it was a mistake, admit it; if you made a mistake, admit it. Just covering things up is never the right decision and something so bad as this decision cries out for an explanation. This is exactly why fans hate VAR.
For me, VAR authority is the wrong way round for decisions where interpretation is required.
If you take the West Ham v Man U pen, this is how a rugby referee would have dealt with it:
1) Instinct not to give a pen and play on.
2) When play stops, David goes upstairs and says, 'Michael, I want to see collision in the penalty area. My onfield view was no penalty, I want to see if there's anything more to it.'
3) Michael 'Here is the footage David'
4) David 'Right what I can see is two players running into the same space and coming together. Although there is some contact, this is not a foul. Michael, your view?'
5) Michael, something along the lines of 'That interpretation is a fair representation of the footage'
6) David 'Thank you Michael. I will stick with my onfield decision of no penalty'
In other words, the VAR official has a lower authority to than the match referee. This is because
he's the one reffing the game. I mean, it's not rocket science.