Why is it that...?

Its because Republicans love to get caught up with the unimportant details like that. They try to divert the voters' attention from the real issues to discredit their opponents without having to resort to actual civilized debate. And conservatives just love repeating stuff like that, like the whole Al Gore house energy thing, for reasons I'm not aware of. Perhaps it makes them feel better, or perhaps they think statements by Obama's pastor really are more important than energy prices or hundreds of thousands of people dying in Iraq. And Democrats try to fight fire with fire, because they are forced to if they wish to be competitive. All the while, we are serving the goals of the Republicans, because they really are better at those kinds of tactics, and their base blocs are more responsive to it. Just look at Karl Rove and the "flip-flopping" Kerry.