1.His interpretation was that God saw man becoming too sinful(i.e. scientific according to Nietzche) so he decided to drown them. To Nietzche this is a perfect example of how Judeo-Christian leaders put down knowledge in order to stay in control of their ignorant followers, and I can honestly see where he's coming from.
i disagreed at first, because the theme is not present in the actual story. however, the the extra-biblical literature it is. the enoch (watchers), it's azazel giving men TECHNOLOGY that promts the flood, and not the nephilim or men's wicked ways. it's the fact that they now had weapons.
2.The only real moral lesson I saw is that Noah's ark saved him while all the sceptics of a world flood drowned, meaning sometimes you have to do things despite what others think of you for it.
i don't recall anything about what noah's neighbors thought. i think that's from a very apocryphal later joke or song or something. it never specifically says what noah did to find favour with the lord either.