I agree that being a member of the KKK is in bad taste, and racist.... But what Bill Maher said on his show was a joke, people took it as offensive, then he apologized, but he would say it again in a heartbeat to the right audience. Ice Cube said that blacks own that word and white people have no business saying it...... but if it is in the context of a joke, like it was for him, I don't think he needed to apologize or wanted to, he just did it to save face...Then after that, all was forgotten because he is a left progressive.
I had a friend who is Filipino, he dressed up as Lil Jon, didn't have to paint his face black, he was already dark, but not quite dark enough. He went around saying OOOKAAAY! all night long, it was hilarious. If he had actually painted his face darker to look more like him, would that have been racist? In contrast, if he were white, would it be different as well?
I think Neeson was just conveying how good people can sometimes have impure thoughts due to circumstances they have been in, and emotions can sometimes takeover leading to irrational behavior (that is what happens to people with PTSD too, we don't call them racist). Maybe a bit of a confession as well hoping that the majority of people will think he is overall a good person (I guess because he is an actor?)
But this is a problem that minorities do face. Back then, blacks were about 11% of the population of the US. So, when the majority of people that you see, day after day are white, and nothing like this ever happened before (I'm not sure exactly where he was at the time, I'm assuming US), the one time that this does happens to a loved one, and the person happens to be black(11% of the pop, and maybe even less depending on where he actually was).... it is going to negatively affect your thoughts of people in that culture, whether you know it/like it or not. At least that would be a normal reaction to a horrible personal experience. It doesn't make it right, it is just human nature. People don't seem to have any empathy for that.