"The first word above might be used after an enemy challenged the
bravery of the speaker. "

"The second might be followed by an explanation such as, 'We are not
willing to kill you because we require your services.'"

"The third word would be used to emphasize killing, as opposed to some
other form of punishment."

These explanations are the key. The translations not only say what the sentences mean; these explanations show how a Klingon might legitimately use the sentences. They are context. There is no whiff of taboo mentioned in these canonical descriptions of how to use these sentences.

The taboo is not simply the combination of certain syntactic elements. The taboo is in admitting fear using certain syntactic elements. If you're not admitting fear or appearing to do so, there is no taboo.

-- 
SuStel
http://trimboli.name