I think you probably actually care about the team’s present-day success. At least, enough to feel genuine disappointment when they fall short. I’m guessing probably because you actually invest time in following the team. No shame in that, if that’s the case. That’s how it was for me when I invested time in any team.
The “bandwagoner” people I’m talking about care about being in with the popular crowd and associating themselves (in some illogical way) with a historic winner. I think it is within reason to assume many of us grew up with a kid or two like that, and were annoyed. Seeing it happen with adults is not only annoying, but disappointing (but that may be my issue). They care enough to be part of a popular conversation and relate to others, and that’s about as far as the fandom really goes. IMO, of course, based on personal observations. Different values for different people.
I grew up with a kid in the late ‘70s and through the ‘80s. First, he was diehard Steelers. Then, magically, he was diehard 49ers. I bet I know who he “loved” when the mid-‘90s rolled around. We had since gone our separate ways in life, so I can’t say for certain . . . but by that point, it didn’t matter — I already had personal experience with bandwagoners and knew they annoyed me. Self-proclaimed greatness and living in the past are two other things that annoy me. I don’t think I live on a small island in that regard.
Anyway, that’s my perspective on it. Since you asked.