I've seen most of season 3 and 4 of 90210, and I never got the whole 'I Hate Brenda' thing either, I mean out of all the characters on the show, I just didn't get it. I mean, if people are hating Brenda because of Shannen's actions, then why wasn't there an 'I Hate Donna' club, seeing as though Tori obviously only got her job becuase of her dad, and she cannot act for toffee.
And Kelly stole her best friend's boyfriend, what about her? Anyway I think a lot of it must have come from jealously from the girl fans because Shannen got to kiss Luke Perry and stuff.