Someone (usually) new to a
fandom who tries to change the medium to
meet their
personal criteria, or shames existing members for liking established parts of that medium; especially before they've taken the time to properly understand the existing culture and assimilate into it.
A: "Dude, I LOVE superhero movies and have seen several, but they're way too violent. It sets a bad example for
kids, and if you support that you're
disgusting. I'm tweeting at all the publishers right now so they know that
REAL fans won't stand for it anymore."
B: "Fucking tourist."