What you are saying is, of course, true.
However the bigots and the racists and the sexists are also victims, of their own stupidity, lack of education but most of all society. To be able to understand and appreciate modern diversity requires a certain amount of intelligence and also (imo) a third level education(think of all the terms involved in modern diversity discussions). People like Martin Luther King achieved great things because they were willing to see beyond their opponents flaws. I do not believe meaningful changed can be achieved by lecturing the ignorant from a pedestal.