The explanation for the record turnout is simple: hate is a far more powerful motivator than love. A groundswell of a positive support for a candidate will never equal, even in its most extreme cases, a groundswell of negative turnout against a perceived bad president (almost always a sitting president).
But you all should've known that already. Look at the entire existence of 24 hour cable news networks: it's all bad news all the time. It's fearmongering, that's the way to keep your viewers invested.
