This is poor analysis in my opinion. I am no defender of Fox News, but this feels more like red meat for the faithful in that it confirms all their priors. Of course it is the evil FN that started all this and led to where we are.

Monocausal explanations should always be treated as suspect, especially when they confirm your priors.

I would be interested to see if watching fox news leads to a decrease in government trust, or vice versa - after all correlation is not causation.