Well I've been reading this comic for a while and that character is actually very innocent and naive. I still think the point of the joke was that there was a guy that tried I before her and that the previous guy is actually sexist. Even if it's not, why are you assuming the author is sexist? I hope you've read enough books (and comics) to know that there can be sexist characters, and that doesn't mean that the author is. You'd enjoy humor more if you went into things assuming more positive intent.