Even though Facebook has a reputation for a strong, engineer-driven culture, the fact is that at a certain size the politics are complicated. It's not a question of whether you have to play politics or not, but rather what do the politics look like? This is why I like working for startups, there just isn't any room for politics, and you can sink or swim based on highly visible contributions. Even though Facebook makes the claim that as an engineer you are responsible for the experiences of X million users, in practice that's not how it works.
Good luck in your new job.