A contributing factor may be that media literacy is taught incorrectly in schools.
We now have armies of bloggers who were never trained in investigative journalism, never taught how to be objective, not taught properly who to trust or how to figure out who to trust, and probably not taught adequately about cognitive biases and the negative effects they can have. If professional journalists sometimes make mistakes evaluating information (and they do), how much more likely is it that these untrained folks will come to incorrect conclusions?
It’s most inconvenient that the rise of non-journalists-playing-the-role-of-journalists has risen at the same time as the average quality of mainstream journalism has gone down. I’m extremely worried about this crisis of trust, which seemingly elevates the kookiest ideas to the same level as well-evidenced facts. Even billionaires can sometimes believe this stuff. Even the president will spread conspiracy theories now and then!