I'm not writing this about one fanbase in particular and bandwagon fans (though I would like to take the moment to laugh at Detroit because they count Kid Rock as one), but just bandwagoners in general. Every fanbase in every sport can fall victim to them. They're like the great plague of sports, at least to the die hards in a market. To the owners of sports teams, they're perfectly a-ok, because they present a new business opportunity. New butts in seats. Winning new fans is the goal for much of today's sports teams, because money is what makes a market viable. No one wants to see 3000 people in the stands and more empty seats than foam fingers. More people = more word of mouth = more publicity = more people = more money. Money is good for the franchise, so why do the fans who've followed a team through good and bad times resent the newbies?
Is it the stupid questions asked during a game? Is it the fact that they're oblivious to any aspect of the history of the franchise before the date that the team became successful? Or, is it the same deal that used to tick you off in school? You know the drill - you work your butt off on a project for two months straight and do a great job. You think you're going to get an A, the highest grade in the class... and then along comes someone whose parents bought them the goods for the project and did it all for them the night before. And they get the A+. Just grinds your gears, doesn't it?
Apply that to the bandwagon fan - you've suffered through low years of a franchise, through no attendance, through the doldrums. You know that sports are go in cycles, and as soon as this one is over your team'll be back to being great again. And then boom - you're right! The team's great again! And then all of a sudden people who didn't give a flying flip 2 years prior care about the team and consider themselves super awesome fans, riding the coattails of success. And, of course, invariably giving your team a bad name, because they tend to be obnoxious and make more noise than the people who have been going to games for 40 years or so.
So, which is it? Necessary evil to get the franchise some money, which gets them new players, which might make them be a bigger contender? Or, do bandwagoners irritate you so much that you would prefer they go the way of Towel Boy's towels (and dignity) - over the railing?