1) Why did our society make this error?<p>Racism. Victims are most available in the disenfranchised of our society and black people have always been disenfranchised in our society.<p>2) How do we prevent making the same mistake in the future, regarding other issues?<p>Stop being racist.  Stop disenfranchising entire segments of the population. Start investigating those in positions of power and stop the cover-ups.