That's what concerns me, It's fine to say you don't endorse something. It's a different matter to say you don't endorse it UNLESS God says it's ok. Particularly when the world has no consensuses on God.
It could be said that "The world" does have a type of consensus on God. We tend to think of anything outside the knowledge of the God of the bible as "the world", and the world hates God, or does not know God.
However, I think you mean that it appears that many people have different ideas of God, many different religions and so forth. To that I'd agree.
There is nothing in the biblical Gods word, or character, that supports the killing of innocent people, but we have to define innocent. For God that would be righteous. Non of us are righteous; not me, not you, none of us.
That seems a license to kill right there, and some have use that type of thinking to do just that in the name of God. They where wrong, and it's because they are unrighteous. However, we need to draw a distinction between God and us. Us being you and me.
My being a believer does not make me any more righteous than you in the eyes of God. we are the same; Sinners by nature, but I am saved. Saved from what? Gods judgment.
Are you saved? I don't know, You may be. You may just not know it yet. In fact I'd say there is a good chance you are because you are interested in God. If you where not you'd not be here or asking questions, or thinking about God in the terms you've expressed, and making good arguments.
How do I know this? Because I once was a non believer too. But, Unlike you, I did not even think or care about God one bit. I never questioned that which I did not believe in....another story.
If your concern is that one might endorse killing because they think God says it's OK, realize that those who don't even believe in God endorse it already without God. So what's the difference?
In the case of the flood, God was not killing innocent people. Even the people He spared where not innocent, just people He chose for His plan of redemption.
God created us with Volition. (the faculty or power of using one's will) He did this because that is the only way true Love can exist, but He used our will to bring about His.
The story of Noah is not about killing people, as much as it is about loving mankind, you and me, and bringing about a plan to reconcile us to Him.
When you read the stories the bible offers, try not to miss the message. It's rich in meaning far beyond the surface of what we tend to see at first.
God bless, and keep questioning everything. Especially God.