You shouldn’t have to do this. You shouldn’t have to wade through complicated privacy settings in order to ensure that the companies with which you’ve entrusted your personal information are making reasonable, legal efforts to protect it. But Facebook has allowed third parties to violate user privacy on an unprecedented scale, and, while legislators and regulators scramble to understand the implications and put limits in place, users are left with the responsibility to make sure their profiles are properly configured.
Facebook’s Platform API is what allows third-party applications to access your Facebook data. Disabling this will also disable your ability to “log in” with Facebook, but if you’re looking for a way to tighten down your account without deleting it, this is worth considering.