Apparently the lesson to be learned from the story of Noah is that omnipotence is rather indiscriminate in its actions. Hey, the whole world got flooded because there were wicked men - by comparison, a believer or two getting caught in the cosmic bug zapper directed at you is no big deal ;)
The Noah story is about wiping out humans interbred with nephilum, you see Noah wasnt sinless or anything like that
he just wasnt from any mixed marriages or fornications if
you prefer. If you care to read the geneology in Luke you will find Noah in there, it was a massive gene pool cleansing. If you care to know what nephilum are they were described as giants or fallen ones.
Pretty inefficient if you ask me. After all, when the CIA wanted to exterminate African Americans, they invented crack cocaine and the AIDS virus. You;d think an omnipotent being could come up with equally creative solutions.