In verse 5, god saw the wickedness of mankind. The chapter has not specified how wicked man were at that time. Can we assume that not ALL men are wicked to the same degree.
God then decided to kill ALL men on earth except Noah and his family.
I have a problem with this.
1. God has indiscriminately killed ALL (except Noah and his family) without consideration of the different levels and kind of wickedness. Is that that unjust?
2. Because Noah himself is righteous, it does not imply members of his family is also as righteous. But again, god indiscriminately saved all his family. Again another unjust.