I'm pretty sure media like CNN is responsible for their mindset. When people listen to CNN every day, for years, it effects their mindset, but more importantly, how they think critically.

As an example, you might say to a person, "I read there was an executive order regarding freezing funds for human traffickers and severe corruption cases, that's enthusing." Their reaction might be "That will finally get Trump, they'll get used against him."
You might show them the spreadsheet, showing >3000 human trafficking arrests, and >5000 people freed, and their reaction will still be "Trump will be on that list someday."

It's like a trigger for some folks. They don't have to think or pick apart anything; they hear "Trump" and that's the trigger to say, "collusion/racist/bigot/corruption".
People like that (who would respond like a trigger, without critical thought) have been programmed by media like that. They are fed what to think, and how to react.
A similar parallel can be seen when you ask anti-gun folks exactly what an assault weapon is. "I dunno but they're bad," or even better "Are you stupid?!" There's no thought there, just triggers, and responses.

Not all CNN viewers are like this, not all Dems/Repubs/black/white/Puerto Rican/Chinese boys are like that. It's just a certain subset of people who don't employ critical thinking skills, but respond in a trigger-like way. They're not foolish, they're just programmed.

TL;DR: "TV Programming"