Progressive African-American? First of all, unless they lied, Obama is biracial, half black, half white. Secondly, he divided and set the country back more than 50 years.
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 .