Referees don't cost you the game. Neither do individual players. If Florida was better they would have won as a team. They weren't. Congratulations to the Islanders. Tavares doesn't get enough love in the NHL.
Just for arguments sake, if a series is very evenly matched, faulty officiating can be a difference-maker.
But anyone saying that the series should rightfully be Tied, still doesn't mean that the Islanders wouldn't have won it. But it's a tough pill for the losing side to take, knowing that certain calls didn't go their way.