People in general get very attached to their ways of life. They think that the way things are is the way things are supposed to be. Because of this, they can get very defensive when their way of life is (they feel) being attacked.
I believe that this is why there was a sometimes ugly backlash against the Civil Rights Movement. Whites in the South felt that segregation was the way things should be and that their society would fall apart if it were banned.
Whites in the North did not want black people living near them, for example. They felt that threatened their way of life. That's why Martin Luther King Jr. was hit in the head with a brick while leading a march in the Chicago area.