if you look at God's reason for the flood (to eliminate evil men)
No, it was not. Reread Genesis again. The reason was to eliminate the offspring of the Nephilim (fallen angels) and the daughters of Adam. Among Adams' descendants, only Noah & family did not intermix.
5 And GOD saw that the wickedness of man [was] great in the earth, and [that] every imagination of the thoughts of his heart [was] only evil continually. 6 And it repented the LORD that he had made man on the earth, and it grieved him at his heart. 7 And the LORD said, I will destroy man whom I have created from the face of the earth; both man, and beast, and the creeping thing, and the fowls of the air; for it repenteth me that I have made them. 8 But Noah found grace in the eyes of the LORD.