I'm actually not surprised that journalists overestimated Hillary's chance of winning. As a group, they are predominantly coastal and almost uniformly college educated. Both of those groups broke disproportionately toward Hillary.

Non-college educated Americans broke disproportionately toward Trump. It would seem given the relationship between college graduation and cognitive ability (the bottom 20% in cognitive ability rarely graduates from college) that this is reasonable support for the correlation of fake news belief with Trump support.