I'm sure the black community is very proud that America finally has its first black president, and it's natural that this pride is reflected in a sky-high approval rating among black voters -- to see one of their own holding the highest office in the land.
The rest of America is proud that we now have a Great president in the White House, which is why Obama's approval rating remains so high among everybody else.
How high? Well, just compare Obama's approval rating today against Bush's when Dubya left office. What was that difference? Night and Day.