Targum Pseudo-Jonathan on (Genesis 6:11) isolates the cause of the Flood. "The earth was corrupted through the inhabitants thereof, who had declined from the ways of righteousness before the Lord; and the earth was filled with rapine."
The Targumist makes the verb active. The earth did not simply become corrupt; it was corrupted by people. Ecology and ethics are fused. What human beings do, the land absorbs. Violence — chamas, rendered here as "rapine" — filled the world. Theft, exploitation, the strong devouring the weak. This, more than idolatry, more than even the fallen angels, is what finally triggered the Flood.