Murder is never good. Is that open for interpretation?

Good and Evil is not open for interpretation. What is open for interpretation is our perception of them, because we’re not without fault.

However that doesn’t mean that Absolute Good (and Absolute Evil as merely a perversion) don’t exist.

All of our intentions and actions are contrasted against Absolute Good, there further we are from that the more evil we are. And the interpretations you spoke of are a constant search for our position with respect to this Absolute Good, which is God.