Nicholas Meyer is a wonderful storyteller but he lacks a regard for established Trek lore or canon. I'm surprised Leonard Nimoy didn't reel him in more with some of the questionable out of character moments with the TOS crew. At that time they were more interested in reflecting the then current news of the Soviet Union collapse of 1991 more then anything, and they didn't care to address TNG's Yesterday's Enterprise
or anything else we knew about these characters from the TOS movies or series. David dying at the hands of Klingons seemed like something that could be mined to create a bigoted Kirk that could move the plot along and they ran with that, despite Kirk not showing that much hatred towards Klingons in any previous movie or TV episode.