Yes but the sign in stuff is within your control too. Simply logout or delete the cookies, and don't use sign in with facebook. Simply having a facebook account (even under a pseudonym), doesn't mean you have to start using login with facebook. I try to use Facebook in the most minimal way possible—I have an account and can message people, but I don't use it for anything that I don't need it for. I try to ensure I get more out of it than it does from me. I don't voluntarily fill out my profile with more information than necessary.