Boston liberals tend to be fair-weather Patriots fans, because they consider Patriots fans to be conservatives.
I grew up in Connecticut. It is the height of hubris to claim six entire states as the fan base. Our parents were nearly all Giants fans. Many of us picked at team that was competitive in the 70s when the Giants stunk. I hated the Cowboys, so I picked the Rams. But my peers were Steeler, Raider, Cowboys, Dolphin fans. In prep school, we had plenty from Massachusetts. They didn’t care about the Pats even when they had Russ Francis and Steve Grogan. They cared about the Red Sox. They rooted for the Celtics. They celebrated the Bruins at times. Years later, they cared more about BC’s Doug Flutie than Drew Bledsoe.
Now, some of my nieces and nephews are Pats fans, because of the Dynasty. Misguided, but understandable. They aren’t going to spring for tickets in Denver to see a game, though.