Gibson is indeed an alcoholic, anti-Semitic fornicator. He is nominally a Catholic, but if he was simply some ordinary Catholic instead of a celebrity, he probably would have been excommunicated, the sorry scumbag.
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .