Because he is the President. If the economy were going gangbusters, we would be giving him the credit, just as many gave President Clinton credit for the 1990s

Because he is the President. If the economy were going gangbusters, we would be giving him the credit, just as many gave President Clinton credit for the 1990s boom. President Obama is the one everyone looks to for leadership, so he is the one who gets praised or damned when the economic statistics come out every quarter.