The only truly intelligent Leftists are willfully evil. They’re relatively rare, but without them the rest of the Left would flounder and sink.
At the opposite end of the Leftist spectrum, only complete idiots could be morally pure. And these…probably don’t exist. A morally pure moron is both honest and good. Therefore one of the few things he would know is not to mess with anything he doesn’t understand. He’s wise, not smart. Think Forrest Gump. Since the essence of Leftism is meddling, it seems impossible for a truly good person to be a Leftist.
Between the statistically insignificant poles are teeming hordes of…the willfully stupid. They range the gamut, their intellect usually varying in inverse proportion to their morality. But unless they sear the conscience, every one of these Leftists has a vague awareness of moral and ideological error.
This is what accounts for their universal bitterness and hatred.