Saying nigger or nigga in my opinion is not a damn huge deal. I think it's fucking stupid.
It's just how you use it. How Kramer used it, that was ridiculously racist. Saying words doesn't make you racist. What you believe in does, and you thoughts towards a group people make you racist.
That dude, hates black people with a passion, he is a racist asshole.
In a completely off note though, I think there will be a ridiculously less amount of racists in around 50 years after this last couple of generations die out. I think "black racism" will die out in time, along with all the racists who believe that shit.