Someone who worked at Facebook for the better part of a decade responded that they felt the media coverage was unfair to Facebook. You were suprised by this response because from an outsider's perspective you felt that Facebook employees should be apologetic? What makes you more qualified to judge whether the public perception was accurate as compared to someone who actually worked there - an "FB vet" in your own words?
Having dug into the Cambridge Analytica story, I can see a number of reasons why Facebook workers would feel wronged by the coverage. In particular, many outlets omitted or downplayed the fact that Cambridge Analytica had lied about the purpose of their data collection, falsely claiming that it was for academic research. Dozens of other academic institutions were similarly allowed to solicit data from users, yet those go unmentioned because most people don't see users voluntarily sharing their data for academic purposes. But that's what Cambridge Analytica was, from Facebook's perspective. The picture painted by the media was one where Facebook brazenly sold people's data to nefarious actors, when in reality Facebook treated Cambridge Analytica just like other academic organizations in allowing them to solicit users for data - except it turned out that CA had lied about the purpose of its data collection.
This story leaves makes me more empathetic towards your interviewer. If my company was so throughly demonized by the media such that candidates discount my own experience actually working at the company and are "floored" when when I tell them that the reality is different from public coverage, I'd be pretty salty too.