A Private Little War; why would the Klingons even bother with this planet?

An otherwise good story exploring the (then current) Vietnam conflict with a SF twist, but something that has bugged me over the years is that it feels below what a warrior race like the Klingons would even bother with.

The people on this planet are obviously pre-industrial, and while the Klingons probably don't have something similar to the Prime Directive, it just feels like them starting trouble on this world is nothing more than the class clown wondering what he can do today to make trouble at school. Yes, the planet is alluded to being in disputed space, but it just comes off as beneath them.

Yes, I am aware that Starfleet was there before themselves, but under the guise of travelers from another area of the planet and in true Kirk fashion, he let's it slip to Tyree he's actually from farther away, so while Kirk and co. probably should have just observed from afar, it's still better than the Klingons apparently saying "hi, we're from the stars. Got a dispute with your neighbors? We have a solution"

While I know it wouldn't have made much of a story, I always hoped TNG or even DS9 would have followed up on this in some way to just say what eventually did happen after Kirk gave Tyree's people the flintlocks to even things up.