Dealing with differences needs to be encouraged gently, whether with ideas or with people.
As described in “People with Low Self-Esteem Show More Signs of Prejudice”:
When people are feeling bad about themselves, they’re more likely to show bias against people who are different. …People who feel bad about themselves show enhanced prejudice because negative associations are activated to a greater degree, but not because they are less likely to suppress those feelings.
The connection between low self-esteem and negative expectations reminds me of related research on the impact of a value-affirming writing exercise in improving the academic performance of minority students:
In 2007, [Geoffrey Cohen from the University of Colorado] showed that a simple 15-minute writing exercise at the start of a school year could boost the grades of black students by the end of the semester. The assignment was designed to boost the student’s sense of self-worth, and in doing so, it helped to narrow the typical performance gap that would normally separate them from white students.
After two years, the black students earned higher GPAs if they wrote self-affirming pieces on themselves rather than irrelevant essays about other people or their daily routines. On average, the exercises raised their GPA by a quarter of a point.
Think about the things that are important to you. Perhaps you care about creativity, family relationships, your career, or having a sense of humour. Pick two or three of these values and write a few sentences about why they are important to you. You have fifteen minutes. …
In a university physics class, Akira Miyake from the University of Colorado used [this writing exercise] to close the gap between male and female performance. … With nothing but his fifteen-minute exercise, performed twice at the beginning of the year, he virtually abolished the gender divide and allowed the female physicists to challenge their male peers.
Helping people feel better about themselves seems like an obvious, “everybody-wins” approach to improving education, social relations, and accepting different ideas.
 T. J. Allen, J. W. Sherman. Ego Threat and Intergroup Bias: A Test of Motivated-Activation Versus Self-Regulatory Accounts. Psychological Science, 2011. DOI: http://dx.doi.org/10.1177/0956797611399291
 Cohen, G.L., Garcia, J., Purdie-Vaughns, V., Apfel, N., & Brzustoski, P. (2009). Recursive Processes in Self-Affirmation: Intervening to Close the Minority Achievement Gap. Science, 324(5925), 400-403. DOI: http://dx.doi.org/10.1126/science.1170769
 Miyake, A., Kost-Smith, L.E., Finkelstein, N.D., Pollock, S.J., Cohen, G.L., & Ito, T.A. (2010). Reducing the Gender Achievement Gap in College Science: A Classroom Study of Values Affirmation. Science, 330(6008), 1234-1237. DOI: http://dx.doi.org/10.1126/science.1195996