Have you ever heard of the False Consensus effect?
The
false consensus effect, also known as
consensus bias, is a pervasive
cognitive bias that causes people to “see their own behavioral choices and judgments as relatively common and appropriate to existing circumstances”.
In other words, they assume that their personal qualities, characteristics, beliefs, and actions are relatively widespread through the general population.
This bias is especially prevalent in group settings where one thinks the collective opinion of their own group matches that of the larger population. Since the members of a group reach a consensus and rarely encounter those who dispute it, they tend to believe that everybody thinks the same way.
Additionally, when confronted with evidence that a consensus does not exist, people often assume that those who do not agree with them are defective in some way