We had been seeing God trying to create a good world
and being frustrated .

First he created man who had to have some agency to be a being.
Man was tricked into disobeying and had to be removed.

When the world became completely evil , God destroyed it
to start over.

A person murdered and got a special punishment but
murder became commonplace

He frustrated cities but these were rebuilt.

Here he is separating a people to start over.

All this with good intentions for a favorable outcome.