lol WHAT? His general hatred towards ALL KLINGONS doesn't make him a racist? "I've never trusted Klingons and I never will. I can never forgive them for the death of my boy."
Seriously... WHAT?
You're right there on the edge, though. It's simple: James T. Kirk's racism...
So there are REASONS why he is racist against Klingons. Doesn't change what he is or what he believes.
No, it's a feeling of hatred and antipathy towards an entire race of people he (thinks) he knows enough about to make a universal judgement call. That doesn't require him to adopt a human supremacist theological position or anything, he just happens to genuinely believe that the galaxy would be better off if Klingons weren't in it. That's a racist belief, and even Kirk seems to realize this in Rura Penthe when he says "I was so used to hating Klingons." He's realizing that his beliefs and attitudes towards Klingons were based on prejudice and emotion and not based on any meaningful experience with them AS PEOPLE and that his judgements were ultimately flawed.
True as it is that Kirk's experiences lead him out of his hateful bigoted mindset, the WORD for the mindset he eventually abandons is called "racism."