I have quite a few friends who have worked and still do work for Facebook. I used to know someone who worked on their "security" team that truly had some frightening powers re: privacy, but with the excuse that it's ok because of stories of saving some kidnapped child's life, or helping track down someone with terrorist connections because they had Facebook messenger on their phone so they could pinpoint their exact location and report it (along with message history) to the police.
I know a guy who worked on a content moderation team and has been severely psychologically affected as a result. Like, he's not the same guy anymore. But he still works there and doesn't seem to consider taking any other job. I think it's because once you've seen all sorts of horrific images and have knowledge of heinous acts going on in the world after you're put in a position of policing them, you feel like the problem is bigger than yourself and your needs are secondary. It's sad, though.
I've never heard any of the people I know talk negatively about Facebook in any way, especially not a "wow, I can't believe I work for these people." There's always a focus on the good they're doing, and how the good outweighs the bad. After Trump got elected, there was all sorts of talk about how Facebook is bringing people together with feminist and anti-trump groups, ignoring the other facts. When Zuckerberg was testifying to Congress over privacy issues it was all about how he's being misrepresented and Congress doesn't understand the internet.
Only recently have I detected some small dissatisfaction from someone who has worked at FB for 7+ years, but instead of jumping ship entirely they switched to working for a different Facebook owned brand.
But I hear the pay is great, benefits are great, stock options are great, and the Facebook kool-aid is a mighty potent drink.