First of all, the Ambassador was referring to justice, not honor. As a diplomat, he knows better than to use a word that has a culturally-specific dual meaning just to be a confusing dick.
On the other hand, the overriding point is that Klingon behavior is wildly inconsistent with Klingon rhetoric. Strictly speaking, they do not even behave honorably by their OWN standards 90% of the time, and Kruge's conduct is no different. Thus when Sarek puts him to task for Kruge's obvious crimes -- attacking Grissom without provocation, murdering David in Cold Blood, etc -- the Ambassador doesn't use the "Klingon honor demands it!" copout, he once again alludes to the existence of the Genesis Device as justification for anything Kruge might have done.
Ambassador: "We have the right to preserve our race!"
Sarek: "You have the right to commit murder?"
Ambassador:
Klingons, like Vulcans and Humans, have a very strict and ancient moral code that all but the most upstanding of them totally ignore whenever it's convenient to do so. Even by KLINGON standards, Kruge acted dishonorably, but his government will still whitewash and justify his crimes for the same reason Americans still whitewash Iran-Contra.
No, it really isn't. Which is exactly why Kruge basically went rogue -- violating the neutral zone, violating the peace treaty, violating Federation space and acting without orders or authorization from authority -- to do what HE personally thought was more important. Klaa does the exact same thing in TFF and is solidly rebuked for it by Korrd; Korris and Komnel do this too in "Heart of Glory" and wind up blowing up one of their own ships trying to make their escape.
For the record: Korris thought that his renegade action was totally justified and honorable. Worf disagreed, and so did the rest of the Empire.
Klingon honor may be a feature of an alien culture, but that doesn't mean humans can't understand or judge them by it.
