Even Nixon's head as President of Earth ran a weirdly benign and relatively competent administration as President of Earth. Yes, because Futurama is a comedy, but with all of these fictional Presidents, I think many Americans have (or hopefully had) little concept of just how much of our stability and prosperity actually was due to the government. Fictional accounts of how badly a President can fuck the U.S. just wouldn't've landed as plausible with a general audience.