Aaron Ross Powell of the explains how political meddling in what should be our personal decisions turns those with different preferences into enemies.
See also “Why We Fight: How Public Schools Cause Social Conflict,” by Neal McCluskey:
Indeed, rather than bringing people together, public schooling often forces people of disparate backgrounds and beliefs into political combat. This paper tracks almost 150 such incidents in the 2005–06 school year alone. Whether over the teaching of evolution, the content of library books, religious expression in the schools, or several other common points of contention, conflict was constant in American public education last year.