It is his only choice. The only worse thing he could do was stick with them...like he was doing before now.
The man was certainly between a rock and a hard place, on one hand - quiting the church will upset blacks (not all of them, but enough to make a general statement) on the other hand the longer he stayed the more he upsets the rest of the country.
Before Pfleger - Obama, I believe was hoping it could die down and he wouldn't have to quit - like any other politician - he wanted the cake and eat it too.

It is time we examine and measure McCain and Obama for what they are, not what they claim to be - or what the media tells us they are....it is time to get to things that matter the most - namely - the economy.