The vagueness isn't about fact checking its about a personal projection. Morons hear a slogan like "Make America Great Again" and ascribe whatever period or aspect of life to "Great" that they personally identify with as important.

With little thought then it doesn't matter if person you are voting for actually even agrees with you, you've convinced yourself that they do because what else could "Great" mean. So you vote for and elect someone who really has a very different idea of what "Great" means.