Unfortunately for the world, there were fewer than ten righteous men in the whole joint. Those there were, however, were saved.
You're conflating the Flood story with the Cities of the Plain story.
No, I'm extrapolating: If God would spare an entire city for the sake of ten righteous men, how far beyond redemption was the antediluvian world?
Why does god end violence with greater acts of violence? Again, why is his response always disproportionate? Why are
we more temperate and measured in our response to slights against us?