The woman is batshit. The amount of stuff we never see would fill another 20 books. We never see Snape being indoctrinated into the Death Eaters, we never see anything he did as a Death Eater, we never see him with the other Slythering students, we never see him going to the toilet, we never see him doing the spy stuff that he is supposed to be doing, (I don't count the beginning of Deathly Hallows, he's not spying there.)Hell, we never see him having lunch. Are we to imagine he doesn't do these things?
That's the amazing thing - that these people who insist upon being ~shown~ every last little thing have no idea of the weightiness of the books. Hell, JKR would have had to write twenty one-thousand-page volumes to cover every event from 1971 to 1998. :O