Everybody has a show, game, story, artist, band, etc. that they love. However, a lot of fans take their love of a specific thing into the realms of zealotry. I'm aware of the fact that the term "fan" comes from the term "fanatic", but that's irrelevant. The zealotry that I see in a lot of fandoms is ridiculous. There is hate speech, defensiveness, and a severe lack of logical thought that comes with it.
I could write a 5 page report on this, but I don't feel like spending time on it. The point is, you can be a "fan" and not a "fanatic". Its really goddamned easy. Use a little intelligence and don't flip a dick every time someone says they do