This "bullied becomes the bully" thing shows up far too often in fandoms. You'd think after finding a haven where they can be as geeky as they want, they would be happy to make it an inclusive, safe place for anyone who wants to be there. But somehow they get the notion that some people aren't "geek enough" for their arbitrary qualifications, be it their opinions about canon, their gender, their age, whatever. Bully culture needs to be stamped out wherever it shows up. Otherwise we're all just a bunch of hypocrites.