^Yeah, ST V seemed to show a bit of a warming between the UFP and the Klingons after the chill of the Genesis incident. So maybe TUC was building on that assumption. Although it seemed to ignore any such warming on Kirk's part, making him uncharacteristically bigoted toward the Klingons.
Yes, I've always wondered of something happened between TFF and TUC that could explain Kirk's hatred so much. Ofcourse, a Klingon killing his son can be seen as a reason, but we've always been given reason to believe that in the 23rd century, humanity was beyond such petty behavior, hating an entire species for the action of one individual. So Kirk's attitude in TUC was a bit strange.
That being said, TUC is still one of my favorite movies.