I was interviewing with them some time ago and just gave up half way. Those guys are absolute assholes and are hugely arrogant. Not a place I would want to work.
Assuming you are referring to the hardware group and it was after 2010 (when the current team formed), then I have no idea why you would think that. I interviewed there back in 2013, and was quite impressed by how open and nice they were. While not working at Facebook, I have continued to work within the Open Compute Project, and the FB engineers have been great in my experience.
