When you change teams you can come off looking bad in the eyes of other sports fans. You can't be a "die hard" OKC fan or Miami fan next season without looking like a bandwagoner. You won't be able to avoid it. But this is easily negated. If you were a fan of Washington or Sacramento and you're fed up with constant losing and bad management/ownership then it's okay to start cheering for one of the winning teams but to avoid being seen as the bandwagoner you have to stick with that team. No switching over when that team starts losing and another team starts to win. Stick with the team you pick and ride it out.
Fan switches happen all the time it's not really that rare and I'm sure some fans feel like someone is a "traitor" if they would ever leave the team and become a fan somewhere else but what if ownership is terrible? These Knicks fans who want to become Brooklyn fans aren't doing it because of Jay-Z, the Russian owner who's name I have a really hard time spelling, and the black and white logo. No they're switching over cause they are sick of James Dolan running their favorite team into the ground all the time. If these fans want to switch that's fine by me. If you ever want to switch teams it's fine by me. You are allowed to cheer for whoever you want for whatever reason you want. Just have a better reason than the colors.