I suppose the antediluvians were so wicked because they had a nurturing problem, too, heh? Their every inclination and thoughts of their hearts were wicked continually and they filled the earth with violence.
The reason the Israelites "learned evil" that became so ingrained in them was due to their inherently evil hearts! Any child reading the bible can tell you that; for the ancient Israelites were certainly influenced by the pagan nations around them. But they were influenced because that was the inclination of their hearts to begin with. Their rebellious hearts and hostility towards God began at the Exodus and continued throughout all their days. How come they just couldn't exercise their "freewill" to shun evil and sinful influences altogether?
If the Israelites had inherently evil hearts, they had no need to learn evil.
The heart is the place in our soul where we hold that which we value most. Our souls are created by God in His image and likeness. To say our wicked hearts are inherent is to say God created wicked souls.
Good and evil must be learned, neither is inherent. Why do some prefer good and others evil? Who knows? It's a mystery.
They did exercise their free will, they used it to reject God. God did not withhold grace, but they withheld from believing His word.
Actually, the antediluvians were wiped out because their genetic makeup had become non-human except Noah and his family.
As to having a "nurturing problem"? You tell me. I said
only God can teach us goodness, so was it God's fault for poor teaching?