I find Michael Richards' recent performance at the Laugh Factory to be disgusting and completely inexcusable, despite the fact that I have been a fan of Seinfeld for years, and in fact, Kramer was my favorite character! It's obvious that Michael has some serious social problems. Someone who can so easily go from telling jokes to blurting out racist drivel within a matter of minutes really needs to see a professional. He may honestly need counseling or perhaps even medication to deal with his issues.
I believe that even though he apologized, I'm really not certain of the sincerity of his apology. However, I do feel that for those of us that this tirade hurt, we should choose to forgive him to get on with the healing process that we need for ourselves. "Forgive and Forget" is really short sighted. You should never forget, because we learn from our experiences. Additionally you shouldn't forgive so that the perpetrator feels better but rather so that you feel better, and you are able to move on from the situation.
Times have drastically changed, and where many of us have for so long seen a color when we look at someone, now we see a person, a friend, a colleague, or a lover. However, there will always be those among us who keep the hate alive by attacking those that are different to make themselves feel better. I believe in Michael's situation, he was in a situation where he felt that his very livelihood was being attacked. Not only does Mr. Richards make a living off his comedic aptitude, but he has in fact been very successful in his career up to this point.
Most likely he defines his worth through his ability to make others laugh. During this particular performance, he wasn't adored. He was heckled. Therefore he lashed out as a defense mechanism. He chose to put others down to make himself feel better about who he is and how he defines himself. He has no excuse for what he did and what he said, and his apology is not enough at this point. Perhaps he can salvage his career after this tirade, but I do have my doubts about that.