Having lived in other cities who have MLB teams, I know that sometimes the folks who live in those cities, or even states, feel you should be a fan of the team that plays there. I spent 12 years living in Phoenix and I have been here in Colorado for almost 13. When I was driving long haul and working out of Denver, I did that for almost 7. So, 32 years away from my home team, not counting the 9 I spent in the service, and never have I ever considered rooting for another team.
This of course applies mostly to baseball.