How is that stupid? Explain this to me.
Your logic is outdated because sports are global and international now.
This was a hot take to make, criticizing LA fans for rooting for their favorite team after LA was left for dead in 95. Everyone isn't a front runner. To be a Cowboys fan after our past 25 years and not jump on the hot flavor with Chargers and Rams both in the SB hunt actually showed me something this weekend. These people stuck it out and look to be here for the long ride win or lose. Rams in the SB or not.
By your definition of fan, Americans shouldn't watch English Premier League, La Liga, or Bundesliga for example. Those are top leagues in sport and nobody here is within 5 time zones of the action. By your definition it would frustrate you that there are fans of Man U instead of the Galaxy. Whereas the Galaxy does not have the history of Man U, the popularity or the quality.
Point #2: I would think it's more front running to be a fan of a team that just arrived to the city and people just erased the last 20 years like it didn't happen. The fans of teams from far away or usually your strongest supporters because they have to work harder to watch the games, and get information despite the local media trying to push the local teams as the news source.