Research into belief perseverance shows that even when people are shown overwhelming evidence contradicting one of their beliefs that they dig in their heels and stick to the belief anyway. [1]

There's also Frank Lunz's observation that many people form opinions based solely on the emotive content of the words (Russell conjugation [2]) they're presented with, regardless of the facts. [3]

[1]: https://en.wikipedia.org/wiki/Belief_perseverance [2]: https://en.wikipedia.org/wiki/Emotive_conjugation [3]: https://en.wikipedia.org/wiki/Frank_Luntz#Use_of_language