I worked at FB London in 2016-2017, on the Workplace team. It was not like the OP describes. It was great, everybody was super smart and hard working, velocity was significantly higher than any other job I had (incl. my own startup). I easily learned the most at FB in my career (I was ~35 then). I always recommend everybody to apply/interview at FB/G because it's such a great oppty to see a "spaceship" from inside, set your own expectations wrt velocity and impact going forward, and just learn a lot. I'm still playing by the "FB playbook" today.

I left bc I didn't like London, I didn't like the DE role, and I can make a lot more money in Dubai (higher comp, no taxes, low cost of living, high conveniance and luxury).