I sort of agree with you. Until we know what is being said from Ref to VAR, we'll never know if it is fair. He could easily have said "no goal handball" they check and say "we can't say either way" and it is then disallowed. Sort of okay.
Or he could have said "probably a goal" check for handball - they then see what impact it has on the famous five and decide it's Everton, so no goal. Sort of probable.
What we need is transparency of the process, strange how decisions are made. We have a lot to learn from Cricket & Rugby in this element of the game. Personally I'd scrap it, it is ruining football in its current format.
I'm pretty sure the referee rules a goal on the field. The default call is nothing unless you have seen a foul, so I really think the ref and AR have nothing in real time so the call is a goal.
ALL goals are checked by VAR, so the refs default answer to Brentford is the goal (and every other goal this season in the league) is being checked by VAR and if it's handling we will disallow the goal. This stops players from yelling at the ref who isn't even going to be the one making the final decision anyway, which is a fruitless endeavor.
For this specific decision there "should" be less gray area. If it hits his arm no goal, if it doesn't hit his arm then goal. The referee isn't really going to add much to the conversation when there are already 5 plus people watching the replay so I don't think there is much value to the ref going over to the monitor. On a challenge that is a borderline red card, then the opinion of the on field referee would be more valuable because they've reffed the first 70 minutes of the match and are the actual match official. In theory whether a ball strikes an arm is black or white. A lot of red card challenges fall into the gray orange card area.
The referee on the field hasn't seen it 100% hit Gray's arm so he lets play continue, the referee also has to trust his VAR to give him the correct information.
All that said...I'm not convinced it's hit Gray's arm. The angles I saw on TV don't show 100% it did so you would expect the goal would have stood.
More clarity of the mechanics of how VAR works would be helpful, but we're a long ways from having the refs mics feed broadcasted.
I referee quite a bit, not at this level for sure, but most of my matches we do wear mics. Only some matches I work have video review. Every league has different rules surrounding VAR and referees are bound to those rules. The problem as has been stated here is spectators are left in the dark a lot of times.