I mean as for "momentum" being damaged, Vegas still scored a goal after.
It's absurd to blame the refs for four goals getting scored on a PP. Yeah, they opened the door, but that doesn't mean it's their fault that someone ripped the door off its hinges, smashed it into pieces and burned them. What happened was not some inevitable consequence. It was a crazy, crazy thing.
I think when you add in the factors it's more than "well they shouldn't allow that many goals". No they shouldn't. But factor in a long series, a physical series, a game 6 double OT and the guy getting sent off is not just a major part of the your top 9 but also a PKing forward on the team...
And now factor in how the call came about. Neither ref was making a call. The linesman that dropped the puck was no longer facing the play. The other linesman can't possibly have a clear view of what happened (unless all of a sudden a light cross check to the shoulder and chest area is considered a must call). They made the call up based on what they thought happened. Not what they actually saw happen. That's the issue. That's why it's embarrassing and why the whole series of events never should have started in the first place. And that's important regardless of what Vegas did or did not do. It was a massive mistake by an entire officiating crew at a crucial time. Not a small issue of a phantom tripping call but about as big of a mistake that can be made.
This wasn't a borderline call that was legitimately seen by an official as a 2 or possible 5. This was a completely made up 5 minute major call which is akin to attempt to injure. A call and misconduct that I can all but guarantee would get rescinded by the NHL IF Vegas had pulled out the win. Because Vegas didn't win they will try to sweep it under the carpet.
I think what makes it even worse is not just the vegas loss but that they legitimately let honest to goodness dangerous play go and made up a call on a play they didn't see (Fleury getting run in OT not much before the winning goal was scored. I wonder how much just getting run on a similar play messes with his head on the winner?).