I gave up using facebook a long time ago. I still have an an account, but basically it's just a dwindling number of people who wish me a happy birthday every year.
I've never posted anything political, or really anything at all - I don't know why since I would definitely be the target market, but upon facebook's rise I just found the whole thing pointless.
There have been numerous studies (Delete your account: leaving Facebook can make you happier, study finds) that point to increased happiness without facebook.
Anytime I hear someone start a conversation with "I read on facebook..." I just tune out.
So, I'd say leave it asap.