Wow -
While I get what you are saying, bear in mind when you talk about the swing of that pendulum, that, to my knowledge:
No one here ever turned a fire hose on a black person, nor released their dog to attack one.
No one here ever owned another person, whipped that person, or sold that person's family.
No one here donned a white hood, pulled a black man from his home and lynched him.
Of these actions, we of today must plead innocent of direct knowledge, though I was old enough during the sixties to have directly witnessed the civil rights movement and saw and read about them at the time when some of these offenses were being done. Yet, acording to you, these offenses are too fresh to be forgotten or forgiven, so we are required to suddenly HAVE experienced these things with first hand knowledge and avoid non-PC verbage, though few people today could tell you what they were thinking prior to saying what they thought was an innoxious comment.
Since this is pretty much impossible, and as this incident in Oregon proved, we are going to experience growing pains as long as that pendulum of yours is swinging at all because people on both sides who do not know of the past will certainly be doomed to repeat it as intolerance of any slip continues.
I suggest any prejudices being formed today are fresh prejudices based on current opinions, actions, and reactions, rather then white people, for instance, consciously voicing bigotry as a means of keeping another group of people down because it is historically acceptible. If you have not noticed, organized hatred of others has long been a fundamental foundation of this country as a means to divide and conquer the voting populance.
It works when that population is kept informed via the media every time a politically incorrect faux pas occurs and gets someone fired. That may work for some of us to avoid doing the same, but believe me, others who read that are going to react in a much, much sinister manner.