You are doing the very thing you are accusing me of. You are elevating your understanding to include what you want it to say. The Bible also says do not kill, so using your reasoning, the death penalty is wrong not to mention the many instances where God commanded people to be killed.
Nothing to do with my understanding...if Scripture says it is a sin then it is a sin. The Bible says not to murder. Murder is therefore always wrong...always a sin (even when I lean towards it being justifiable or understandable). If the death penalty qualifies as "murder" then it is a sin. The Bible says that lying is a sin. Your objection does not alter that fact.