I’ve prepared an illustration, which tries to illustrate why and how people may get so different opinions about the same real-world phenomena. The explanation is based on two pitfalls common also in scientific research: selected observation and over-generalization.
As evident from figure, two individuals (person A and person B) may observe the same group of people in real-world via different media, where the focuses of individual media may differ (intentionally or accidentally). Based on media reports, individuals get skewed illustration of a real phenomena and consequently perform generalizations based on a skewed image. Now, two individuals may have completely different images of the same real-world situation and by disseminating their opinion via social media, their images may attract people with the same attitude. As a result, conflict between “believers” may occur.