I can see that but I live among them , I can assure you it's true. Just as true that most Bruins fans can't stomach anything Habs . Very similar.
I just think Bruins and Habs fan are similar on at least one point. Hate and love! That is the rivalry. Plus, fans and players are two different animal IMO.
But I don't see any relationship on what you said... Patrick Roy was a Nords fan and played for the Habs, Lucic played for Calgary and Edmonton, Wayne left the Oilers, Max Dom played for the Habs. Guy Lafleur ended his career in Québec, Orr went to Chicago, etc...
IMO players will go where they want to go based on the city, the team potential, what is good for them, opportunity, money, and with whom they might play. Dubois would not be different.