That is the losers lament(see Bruce Arthurs winging and whining). and it is baloney.
Ottawa defeated the Bruins who were tipped to win and then the Rangers who had defeated the Habs, the Atlantic division leader. 

They endured a  very  difficult year filed with injures and setbacks .. 

Your preferred narrative is the one being sold by sports writers who oversold the Leafs and undersold the Sens to explain why they have all that egg on their faces.