I think its wrong to either throw up you hands and say "humans are mean" or to use past incivility as a rational to treat people poorly, just because they have an honest disagreement with you. We should hold ourselves to high standards of civility and respect for others, not rationalize acting according to the least common denominator. I sense a movement on the left to try to be as nasty as the right. That, quite frankly, is immoral and wrong. More wisdom from the past: two wrongs don't make a right. And do unto others as you would have them do unto you.

The United States Senate, in my mind, is an example of good political discourse. 99% of the time it's a very civil place.