They'll attack anyone who feels different. These are the morons who drive people away from the things they love, because they're so barren in their everyday life that it's the only place they can feel special. They'd rather nobody else was a fan. They don't want other people around, because every other person who likes this thing diminishes them. Since this is the only place in the world they can feel superior, where they can be a big fish in a little pond, they want to keep their pond as small as possible.
Secrets keep people away.
The only reason. But they'll make you feel like crap for not knowing it. They'll try and humiliate you. They'll claim that the way you like the Holy Trilogy is somehow less than the way they like it. If you watched it twice and liked Luke because he was cute when he swung across that chasm thingie, then you're a fan.