Do you have any evidence that any of these things actually happen to a significant extent? Virtually everyone is able to distinguish claims about tendencies from absolute claims, even if they lack the knowledge to express this distinction formally. Here's Steven Pinker summarizing research on stereotypes:

Moreover, even when people believe that ethnic groups have characteristic traits, they are never mindless stereotypers who literally believe that each and every member of the group possesses those traits. People may think that Germans are, on average, more efficient than non-Germans, but no one believes that every last German is more efficient than every non-German. And people have no trouble overriding a stereotype when they have good information about an individual. Contrary to a common accusation, teachers’ impressions of their individual pupils are not contaminated by their stereotypes of race, gender, or socioeconomic status. The teachers’ impressions accurately reflect the pupil's performance as measured by objective tests.