The commandment referred to killing another in cold blood, not to capital punishment. The Torah specified capital punishment for a variety of transgressions, including dishonoring one's father and mother.
And many others, your interpretation aside.
I don't own a Torah. I believe the intent was to stop all killings of all kinds for any reasons.
Muslims make all sorts of creative interpretations as well to justify killing.
I would think, that sooner or later, it will stop and the words finally heeded as the Lord intended.