I think one of the major causes for the disconnect between fan bases the entire playoffs when it comes to series with the Sens is that the fans of Bos/NY/Pit are getting treated to highly biased broadcasting for the American audience, and basically shilling for the US based team.
Having watched all the games throughout the playoffs, its been beyond frustrating listening to the one sided coverage. It's all praise all the time for Bos/NY/Pit and nothing but Karlsson+ boring Sens.
So, for this series, when Pit fans watch the coverage and post game show they are being told how they actually won the game, but because of bad reffing and a standout performance by a lucky goaltender, the Sens won - but didn't deserve it.
Since I am not in Canada I can't attest to how the Canadian broadcast are for the playoffs, but from watching most Sens game throughout the regular season via Canadian broadcasts, they seem to take a much more professional approach to fairness of coverage.
Honestly, this explains why Bos/NY fans still can't accept the fact they lost (because they were told the entire series what a better team they were) and Pens fans are having trouble accepting that this series is going to a game 7.
Oh and don't get me started to the post game coverage with Milbury basically all but saying the Senators literally suck, and don't deserve to even be on the same ice as the Penguins. That montage of missed calls was so one sided it wasn't even funny.