Both very good points. This is the way I look at it, though--just as English has several words for the act of killing, so does Hebraic. The word ratsakh (or ratsach) in the original Hebrew text of the Ten Commandments is actually more equivalent to our words murder or manslaughter. It means the premeditated or unlawful killing of another. That word was never used to describe killing in the administration of justice, in war, or in defense of yourself or your children.
It's my belief that very often the appearance of contradiction within the Bible can be traced back to translation issues where a broad term was used rather than the more specific or more definitive term.
This is a perfectly viable view, but it has two problems arising from it.
The first is that even in one language meaning does not inhere only in words but is contextual in phrases, sentences, etc. One of the things I often find troubling in some schools of Biblical interpretation is the neglect of basic truths of writing. There's an idea that God has to be writing in what amounts to a journalistic style where each word has a single meaning without implication or nuance. This style of interpretation loses the poetic character of the writing as well as the sense that there can be more to a story than just the simple text.
Coming off of this is the implicit idea that the human mind should not be used to interpret holy words in relation to human life. That there should be a single definitive interpretation and that's that. I find this problematic since it in effect cuts off the mind from its primary work of understanding. If one takes the idea that the mind is a creation of God, it seems wrong to hold interpretation in contempt.
There is the rabbinic idea (that I can't find the source for) that whomsoever finds a new right interpretation creates a new heaven. This has lead both to the complex interpretations of the Law and the sophistications of Kabbalism. In the Zohar there is a vast stretch of work just interpreting, "In the beginning, God created the Heavens and the Earth."
The second problem is in the paradox of translation of hold works. On the one hand there is the definite loss of meaning when one goes from one language to another. Shifting to the New Testament, the first words in Greek of the Gospel of John, are (transliterated):
"Ev arkhe ein ho Logos, kai ho Logos ein pros ton Theon, kai Theos ein ho Logos."
Usually rendered, "In the beginning was the Word and the Word was with God and the Word was God."
So first of all, my Greek's pretty bad, but I know enough to know that ark he doesn't only mean the beginning, but can mean things like power, sovereignty, a realm, etc.
To add to that the word Logos was a loaded word at the time the Gospel of John was written, having a number of meanings in various platonist and gnostic groups. Even without those interpretations, Logos as a word has more implications of the English word Story then the English word Word.
Then there's the preposition pros which can have implications of being in the presence of. Then there's the fact that ton in ton Theon is a definite article whereas the second Theon has no definite article. This might or might not mean anything, possibly being stylistic, possibly being an assertion that the Logos was a god, not the God.
And that's nowhere near as much complication as could be created by someone who was actually knowledgable about the language.
Paired with this is the idea of inspired translation, the concept that a particular translation was not just the work of human minds, but divinely guided so as to be as good as the original as far as interpretation is concerned.
So, I don't know if there is anyway to make this kind of thing a simple read the instructions, follow the instructions kind of thing.