There is another element here. I also look at what was known about natural disasters in Biblical times--and what is known about natural disasters today. Humans look for explanations. Not understanding science, plate tectonics, weather patterns, the explanation was God. Therefore the question was, Why would God do this? Their conclusion was to look at themselves and they saw wickedness to such an extent God had no choice. It's ironic, is it not, 'wicked' is not how God saw them, but it was how they saw themselves.
In fact, I do not look at the Bible as a work of "morality fiction". First, morality it not fiction, but great truth. The story of Noah and the great flood, hits on one of the greatest wickedness that springs from mankind and is always causing disaster amidst the population. Even today.
So what does that make God now?
We know that people used God as a filler for things they didn't understand. A flood comes, it must be because God is angry with us. But we now know it's because that's how the world works.
So, does God exist?
The God of the old testament doesn't exist any more because humans have changed, we don't need that God any more.
We have a new God.
We have a God that doesn't live just above the Earth, we know because we've been there and he's not sitting there watching down on us. We have a God who knows a lot more physics and other sciences.
This God fills in the biggest area for humans in the modern world, "love", this God loves everyone, this God wouldn't go around killing everyone in a hissy fit at our violence. We've been VERY, VERY VIOLENT. We had Hitler, Stalin, Pol Pot among a whole host of evil dictators in the 20th century, we had the US invading Iraq and Afghanistan, the rise of militant Islam, Russia invading the Ukraine and playing with all its neighbors, we've got all the other little problems, like the DRC, Sudan breaking up from civil war and South Sudan going into a new civil war, Yemen, Pakistan going mental all the time, we've got high murder rates in poorer Christian countries and the USA.
And this God doesn't give a damn. This God says "they're violent, as long as they come back to church, I'll forgive them and I'll love them"
Proves God doesn't exist. God is just a fictional character who meets the needs of the people. We want love? God gives us love. We need someone to give us control over natural disasters? God will give us that instead. How convenient.
If I write a novel, totally fiction, about some sword wielding guy who lives in a world with magical beings and whatever, and there is morality in that book, does it stop it being fiction because it contains truth in it?
Most books do contain truth, because that's how we, as humans, connect to those books. I think a book that didn't contain truth would be very difficult for people to read.
But what does the Bible do? The old Testament has been around a LONG TIME. And it's been telling Christians not to be violent. When the US went to war in 2003 against Iraq, the population cheered. The Christians, the people who read the Bible, who get told what is moral and what is not moral, cheered, the soldiers took their Bibles to war.
It didn't work. People didn't read the Bible and learn from it. They used their Bibles to justify their war.