I, for one, don't see anything wrong with what Ginger said. She reacted defensively, to be sure, but also assertively and politely. She didn't shriek like a banshee and beat Marten over the head with a broom. The only part you can see as being too intense is her 'WHAT?!', which I see as incredulity/shock rather than actual anger. 'and I do not appreciate it' strikes me as remarkably restrained and polite. Is it the emphatic use of capitalisation that some people are perceiving as 'bitchy'? Or is it her too-close close-up in panel 2?
For that matter, I think it's quite a sad state of affairs when your first reaction to an opinionated woman being assertive is to brand her a 'bitch'. I think we're all perfectly capable of describing someone's behaviour far more accurately (e.g: 'defensive, hostile, aggressive', what have you) without having to resort to gendered slurs.
Maybe some of us are forgetting that we're being sympathetic to Marten because we know him and his intentions, without considering the viewpoint of the girls. If some random 'librarian' tried to instruct me with:
"This is the front desk"
"Here we have a library computer"
"This is a bookshelf!"
You can bet I'd assume he/she was being condescending, and it wouldn't be too far of a leap to assume something like hazing was going on. Something's definitely off. Did Ginger leap to a conclusion? Yes. Would it be fair to expect her to give Marten the benefit of the doubt and assume that Marten merely doesn't know what he's doing? Not really, with the kind of bull he's (unintentionally) pulling.