No worries- I'm not the type that gets riled up, especially about an honest question.
But I did give you an answer, did I not?
Evil is there in our psyche, just like everyone- atheist or believer- has a sense of right and wrong, which to me is powerful evidence of the presence of God.
I am convinced that within all males lurks a murderer and an adulterer. For most of the us, we can control these urges, or society provides inhibitions on their expression.
But when the constraints are removed- for example, when order in a society breaks down because of revolution, then those who have less control over these evil urges- that is, do not have the Holy Spirit to keep them from doing evil, come out of the closet and rape and kill.
Bosnia, Iraq, Rwanda, etc. etc. are all examples of where this happened. Often, it is initiated by one or a few despots like a Hitler or an Amin or a Saddam Hussein. Dictators like that always have the same common traits: they kill indiscriminately, and they have perverted and insatiable sexual drives.
So I believe that is why God allowed the flood to happen- He saw a group of people who had lost all sense of morality, and who rejected the guidance of the Holy Spirit to help them steer away from evil.