Why busing and affirmative actions were the most contentious civil rights issues of the 1970s?

This was because even those who supported desegregation of buses and implementation of affirmative actions sometimes caused issues even among those who supported civil rights. Forced busing and affirmative action created the idea among non-African-Americans that the government legislation was bad and was helping African-American people at the expense of everyone else which they heavily protested and wanted to change.