(or the over-attribution effect)
People are often quick to draw conclusions about the attitudes and personalities of others, even when an external factor or cause may explain that behavior.
Citations: Ross, L. (1977). The intuitive psychologist and his shortcomings: Distortions in the attribution process. In Advances in experimental social psychology (Vol. 10, pp. 173-220). Academic Press.
Berkowitz, L. (1984). Advances in experimental social psychology. Academic Press.