I'd think it more influential on poor Tracey's mind that he got stranded on a hostile planet and attacked by a ruthless army of barbarians. He "hardened" in face of the ordeal, and went on self-defense mode - one he was unable to ditch even when Kirk arrived and offered him a possible alternative course of action, an evacuation.
He had rational and emotional grounds for rejecting the evacuation, of course: he believed it would kill him, and he had gotten protective of the Kohms. That's not particularly insane, that's the sort of behavior one might expect of any military commander similarly stranded. Him being a starship skipper gave his position an "unearthly" twist, though: he was so far from home, with so much leeway for his command, that he would have been in a much better position to defy HQ orders than any of today's field commanders and walk away with it. Good old Captains Drake or Cook could probably have survived a similar incident, careerwise, back in their day...
Drake more than Cook, I guess, because back in his days the Royal Navy wasn't a particularly unified service, and all skippers weren't expected to conform to the same professional mold (heck, they didn't even have uniforms yet!). Whether Kirk's Starfleet called for uniform high standards, we don't know; Kirk himself was quite willing to speak of standing apart from some of his colleagues, of being a special breed. But that "special breed" supposedly included all the starship captains and only excluded the skippers of lesser vessels... I guess Tracey failed to meet some expectations there.
Still, not a completely subpar performance. Tracey wanted to get Kirk out of the way of "doing the right thing". Kirk did the same to Commodore Decker on another occasion. And it was Kirk got his Starfleet opponent killed, while Tracey ultimately didn't, even if it wasn't for the lack of effort...
Timo Saloniemi