They probably mean grammar, since most Google operators do work. If there’s a specific difference in search syntax (other than bangs) though, I’d love to know what I’ve been missing.

Firefox’s creators also have an optional Facebook Container add-on which will sandbox all Facebook cookies in their own Fb-only bubble, for those who still want to use it: https://support.mozilla.org/en-US/kb/facebook-container-prevent-facebook-tracking