Naïve realism (psychology) - Wikipedia
In social psychology, naïve realism is the human tendency to believe that we see the world around us objectively, and that people who disagree with us must be uninformed, irrational, or biased. Naïve realism provides a theoretical basis for several other cognitive biases, which are systematic errors when it comes to thinking and making decisions.

https://en.wikipedia.org/wiki/Na%C3%AFve_realism_(psychology)