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.
"He clapped his captain—his friend—on the shoulder. Yes, this man was very much like James Kirk, in all the ways that mattered." --Christopher L. Bennett-- Star Trek: Mere Anarachy, The Darkness Drops Again