I think the [other] offensive bit here is that it's 'lady' editor, not 'female' editor. 'Lady' and 'gentleman' when appended to a job-role tend to have connotations of amateur/dilettante/hobbyist that 'male' and 'female' don't. Think 'gentleman-thief' or 'lady explorer'. Comes from the days when ladies and gentlemen didn't have to work, so if they had a job it was a hobby rather than a necessity.

And surely female editors aren't so unusual (unlike nine-foot-tall giants) that it would be natural to remark on it every time one is mentioned? In medicine nowadays, the proportions of the sexes is so near equal that a doctor's gender isn't mentioned unless it's relevant (e.g. a patient has requested a male, or a female, doctor for modesty reasons).