This is a personal decision each fan must make, but I agree with your guidelines. It's hard to stay loyal to players who left your team, especially since there is no loyalty between players and teams (re: Damon). That's ok, though. I would jump to a rival company if the situation was right in a heartbeat.

That said, could you please fix that awkward spelling mistake in the 3rd paragraph in the body.
I think you want to say "loved" and not "lover."