on mudslinging and discourse

At the height of the civil rights movement, when things were looking their bleakest, Martin Luther King, Jr. said this to his group of volunteers:
A big danger for us is the tempation to follow the people we are opposing. They call us names, so we call them names. Our names may not be "redneck" or "cracker"; they may be names that have a sociological or psychological veneer to them, a gloss; but they are names, nonetheless-"ignorant" or "brainwashed," or "duped" or "hysterical" or "poor-white" or "consumed by hate." I know you will all give me plenty of evidence in support of those categories. But I urge you to think of them as that - as categories; and I remind you that in many people, in many people called segregationalists, there are other things going on in their lives: this person or that person, standing here or there may also be other things-kind to neighbors and family, helpful and good-spirited at work.

You all know, I think, what I'm trying to say-that we must try not to end up with stereotypes of those we oppose, even as they slip all of us into their stereotypes. And who are we? Let us not do to ourselves as others do to us: try to put ourselves into one all-inclusive category-the virtuous ones as against the evil ones, or the decent ones as against the malicious, prejudiced ones, or the well-educated as against the ignorant. You see that I can go on and on-there is the danger: the "us" or "them" mentality takes hold, and we do, actually, begin to run the risk of joining the ranks with the very people we are opposing. I worry about this a lot these days.

These words bear repeating today, especially in light of what passes for public discourse.