It's entitled nerds that think a movie/series/etc. belongs to them and no one else. When someone who is not an obvious social exile (say, an attractive female) shows love for a fandom, they think that that person must be faking it for male attention, or attention in general since being a nerd is "in" or something. They won't believe that that person is a genuine fan and they'll look for anything to discredit them.
I think in this case though it's young boys who think that girls can't like Star Wars because it's "for boys".