To me a bandwagon fan is one who is a fan only when the team is winning, not one who is critical of things that are wrong with the team. Only a blind homer never criticizes the team.
I think what happens with most of us though is that we are emotionally attached to the star, the team and all that it represents. Most of us will never stop loving the Cowboys. But we do reserve the right to criticize what we think is wrong. It doesn't keep us from watching, screaming, cussing and cheering though. We will do that through thick and thin.
There is another type of fan, though, that I don't really understand. I believe they have a psychological dependency as opposed to an emotional attachment.
What happens with these fans is that they begin to live vicariously through the team. If the team wins it is a victory for them personally. If it loses then they feel like they've just been jacked up themselves and stopped on the one yard line. They feel they are actually a part of the team, in more than just a paying, rooting fan way. And this goes deeper than just saying "we" when they actually mean the Cowboys. Most fans do that, and it's not the same thing.
Those are the fans I pity; the one's who can't recognize that it's just a game being played by other people for our entertainment.
The regular bandwagon fans???...let 'em come and go as they wish. While they're on the wagon they spend money on team paraphanalia which helps to line JJ's pockets to hire better FA's.
Me, I'll keep watching even though I keep getting argyle socks from gay uncle Raul. Because five times he's given me a really great present and I know some day he'll make it number six.