How we cite our quotes: All quotations are from Star Trek VI: The Undiscovered Country.
Quote #1
ADMIRAL CARTWRIGHT: To offer the Klingons a safe haven within Federation space is suicide. Klingons would become the alien trash of the galaxy.
The fact that Cartwright calls Klingons "alien trash" tells you everything you need to know about human prejudice against the species. That being said, this passage takes on completely different connotations once the truth about Cartwright's allegiance is revealed.
Quote #2
KIRK: The Klingons have never been trustworthy. I'm forced to agree with Admiral Cartwright. This is a terrifying idea.
We'd expect Kirk to be gung-ho about making peace, but he has too much personal animosity toward Klingons to even consider it. As we see over the course of the film, this animosity blinds him from truly understanding the crisis going on.
Quote #3
KIRK: I've never trusted Klingons and I never will. I could never forgive them for the death of my boy.
Although Kirk's hatred of Klingons is rooted in his past conflicts with them, the real reason behind it is the death of his son at their hands. Is that a rational reason to hate an entire species? Not really. But we can certainly understand why it's worked out that way for him.