The earth was filled with violence
Of course, God loves each of us and calls us all to repent
of our sins and trust Him to save us. But, he hates it when people commit
wanton, heartless acts to injure one’s fellow man.
But, God hates violence.
In 1st Timothy 3: 3, he insists that the leaders of the church must not be strikers, that is those who will act violently toward others. He mentions not drinking as part of that right afterward but that is not the only thing that causes violence.
God cites the violence which had spread throughout the land as one of those abominations which have so aggrieved him in Ezekiel 8 :17.
So what did the violence entail which had spread throughout the world in Genesis 6: 11? It was one of the things which had caused the whole earth to be corrupt, for all / to have corrupted its way upon the earth. Surely some of this was people - quite possibly along with fallen angels - taking advantage of others, sometimes in a very violent fashion. The wickedness which occurred during this time was something which caused great sorrow. Noah undoubtedly felt this same sorrow, and perhaps it caused him to not have children until he was 500 years old.
Noah had three sons. We know that Noah waited till he was 500 years old. The Bible reiterates about him and his sons, and then goes on to mention that the whole world was corrupt.
We see in verse 10 and 11 that mankind had corrupted his way on the earth. This idea of corrupting means to make it unusable, the exact opposite of the world without sin which God created.
This breakdown, with mankind not wanting God involved, was inevitable with people who rebelled so much against God. And, it shows itself in scientific principles, too.
The law of entropy the second law of thermodynamics shows that things break down over time u
unless some force prevents it; just as God would have done had man not brought sin into the world.
This can be gravity in the case of orbits, for example. God is the Sustainer of all life, no matter where it is, but He could not interfere with man's free will every single time without ending cause and effect. It grieved the Lord that people had corrupted it so much.