People just get upset that their special little underground band has decided that they want to move out of their parents basement and start making some money. I do not see any problem with that, I would sell out in a second. You drive a dump truck full of money to my house and tell me how to write my next album, I'm in, I wouldn't even think twice.
I still think the biggest example of this has to be Sugar Ray. Don't believe me? Listen to Mean Machine, or RPM, then listen to Fly, or any of their later stuff then talk to me. I kind of feel bad for people who bought Floored thinking it would sound like Fly.
Also, The Clash are in no way sellouts. Before Rock the Casbah was released they already had hits with London Calling, Should I Stay or Should I Go and I Fought the Law. The Clash are still the only band that matters.