Or even then.
As for McGivers, Kirk was in the habit of lying about how his crew died. The letter specifying the A&A officer's gruesomely heroic death had no doubt already been sent to the parents, tailored so that they would never feel the need to dig into the story and find out their daughter was traitorous scum, lamentably so far unhanged.
He disabled life support. If that's not lethal force, I don't know what is. Khan was absolutely, positively, trying to kill people.
You seem to be totally misunderstanding the scene. Khan was negotiating. (And when one says "I am willing to negotiate", that by definition is negotiating, so Khan wasn't "being an evil liar in addition wanting to kill", or other such nonsense.)
Really, the way you can twist episodes into a pretzel trying to interpret them in the exact opposite way they were intended boggles my mind sometimes.
It's a function of those responsible for the intending not being all that clever. When one writes a hero, one often ends up describing a villain, and vice versa.
Khan may wear a black hat, but it should not come as a surprise to us that Kirk likes Khan. Kirk liked his villains. He found Kang an okay guy after the Klingon had brutally killed many of his crew (some of them several times over!). In reverse, Kang found Kirk an okay guy after the human had brutally killed
all of his crew (or so it seemed). And it's not a factor of Kirk liking or hating Klingons: he judged Kras and Kruge differently, and they had a different measure of Kirk.
Here the writer may have been trying to write a villain, but he was not simply incompetent - he was deliberately holding back. After all, he wanted the adventure to end with the marooning, and that would only work if Khan wasn't
too evil. Which he clearly wasn't, compared to yer standard TOS adversary.
Now, I can sort of see why Spock Prime would still consider Khan a grave threat. After all, he achieved
barehanded what Rojan did with superior technology; he was a mere human when taking the ship with the same ease as the android Norman did. But Khan of "Space Seed" did not yet warrant the smearing he got from Prime, and Khan of TWoK should not have been included.
Timo Saloniemi