Being an entertainer, you need to capture people's hearts and make them follow you. Being a fan, when you're captured, you follow them, you invest time and money and emotions, you defend them, you fight for them.
So if I say I'm a fan but I dont defend them for every single thing that I see or read, am I not a fan? If I don't fight a war that i think is just a waste of time, am I not a fan? If I don't take every little thing seriously, am I not a fan?
Entertainer's lives revolve around entertaining people. That is their life because that is their career. My life doesn't revolve around them because that is not my career, so am I not a fan?