I am a Denver Bronco fan, and ironically, I date my love of the Broncos back to when I was around 6 or 7. And living in New York, I used to almost never see someone wearing a Denver Broncos hat or jersey, despite the team's (limited) success. If I did, I would approach them, and inevitably they were not a fan, it was someone else's hat, they don't know how they got it, etc. And Broncos merchandise was not easy to find in New York, believe me. I owned a jersey growing up, and I cut the sides of it when it got too small so I could still wear it.
When the Broncos won two superbowls, I saw Broncos stuff being worn all over the place. I didn't have any interest in talking to casual fans about the team, though. It was a strange feeling. However, my feelings about casual fans have changed since I was younger.
In baseball, I used to root for the two New York teams growing up, but I didn't have nearly the same allegiance (or interest) as I did with the Broncos. Then, following the 1988 season (when the Mets won their division and lost to the Dodgers in the NLCS), the Mets decided to sell off their entire team. About two years later, one of the few remaining guys from the team was Kevin McReynolds (McDowell may have still been on the team, too). They showed zero loyalty. I had no desire to root for them. In fact I used to root against them. The Yankees owner (Steinbrenner? Swinebender? something like that) hired someone to dig up dirt on Dave Winfield, who I think is one of the most decent guys to ever play the game, so I wasn't going to root for them as long as they maintained their current ownership. I find myself rooting for specific players I like in baseball. If they get traded, I'll root for them on their new team. It's much easier that way.
The Knicks are another prime example. There's nothing left for me to root for. I can't stand them, Isaiah Thomas, and ownership. If they stay in the cellar and clean house, I'll consider rooting for them again.
Lyle Alzado is the only starter from the great 70s Bronco defenses who didn't retire a Bronco. It was a different time...