If we're in a world where people hiring are put off by experience as a developer at facebook, there are bigger problems. Facebook still has a reputation of hiring good people. It's only the very sensitive that would completely discard that because they dont like the mission of the company.

As I said, I don't identify with anything public facing that they do, and I wouldn't work there (other than to say it's more attractive as in my earlier comment), but I wouldn't consider their individual employees to have any different scruples than the broader workforce.

(I'm talking about technical roles, no idea about the rest)