Re: STVI without the racism
Kirk has one previous reference to "Klingon bastards" and that's right after his son has been killed, and there's no other indications of racial dislike of Klingons until we get to TUC.
He used that phrase again in TFF when the BOP appeared from the behind the cliff where the malevolent entity was stalking him.
"I've sworn an oath to serve and protect the United Federation of Planets- an oath I will fulfill with my dying breath- for in my heart, I remain a creature of duty. I am Romulan." --Captain Sran, USS Naptown