The Letter from Birmingham Jail is a much more significant line in the sand (see comment by Wanda S below). The white bishops whom King excoriates and who claimed that we shouldn't act too quickly to achieve the goal of universal equality are the progenitors of white people today who say we don't need to act anymore because we have achieved racial equality. Both groups (as King says of the bishops) are greater enemies of social justice than are the overt racists like Bull Connor (or his descendants like Tucker Carlson).