Doesn't your God break his own commandment against murder?
From gotquestions.org: There is a misconception that “killing” and “murder” are synonymous. This is partially based on the King James mistranslation of the sixth commandment, which reads, “Thou shalt not kill” (Exodus 20:13). However, the word kill is a translation of the Hebrew word ratsach, which nearly always refers to intentional killing without cause. The correct rendering of this word is “murder,” and all modern translations render the command as “You shall not murder.” The Bible in Basic English best conveys its meaning: “Do not put anyone to death without cause.”
It is true that God has intentionally killed many people. (God never “accidentally” does anything.) In fact, the Bible records that He literally wiped out entire nations including women, children, cattle, etc. Does this make Him a murderer?
As already stated, to kill and to murder are different things. Murder is “the premeditated, unlawful taking of a life,” whereas killing is, more generally, “the taking of a life.” The same Law that forbids murder permits killing in self-defense (Exodus 22:2).
Some would argue that executing the innocent is murder; thus, when God wipes out whole cities, He is committing murder. However, nowhere in Scripture can we find where God killed “innocent” people. In fact, compared to God’s holiness, there is no such thing as an “innocent” person. All have sinned (Romans 3:23), and the penalty for sin is death (Romans 6:23). God has “just cause” to wipe us all out; the fact that He doesn't is proof of His mercy.
Additionally, this reminds me of a call a Christian philosopher got from an atheist pro-choicer. The woman called in saying, “It’s my moral right to do what I choose to do with my body!" The Christian philosopher responded, “Alright maam since you brought it up I’d like to ask you a question. Could you explain something to me: When a plane crashes and some die while others live a skeptic calls into question God’s moral character, saying that He has chosen some to live and others to die on a whim. Yet you say it is your MORAL RIGHT to choose whether the child within you should live or die. Does that not sound odd to you? When God decides who should live or die He is immoral, when you decide who should live or die it’s your moral right.” The caller's response: SILENCE...