It's all there in the Old Testament, we just read over it and miss the plan of God. The demonic angels corrupted the seed of the women and God killed them, all of them. IMO, the "seed" is still floating around in certain people. Study the line of Esau and the Edomites. God hates them and has cursed them. Rome was founded by a branch of Edomites. The Antichrist will come from the old Assyrian empire ( you can figure it out from Daniel and a few other scattered verses that takes an hour to get through, and the pope with be his false prophet).
When you hear someone say God is cruel in the OT, remind them That God never changes. It the same God that gave His Son for His people. God's people were chosen in Malachi when He said Jacob (Israel) I have loved, Esau I have hated. The religion of Old Assyria is mostly Islam.
Now having said all this, Jesus told us that He would return " as it was in the days of Noah, and "as it was in the days of Lot". You can guess what the days of Lot is speaking of, but you get 15 answers about the day of Noah. It was speaking of editing DNA, along with evil such as killing babies, making Chimera's like pigs with human hearts. Stem cell research from abortion, and 15 other things we are doing today, like designer babies and even crossing apes and humans. God created man and looked at what He created and said "It was good". What the demons did was corrupt His creation.
In Romans 1, Paul speaks of us not acknowledging God as Creator so He turned them over to a reprobate, or debased mind. The first sign of this reprobate mind is the woman changed the natural use of their body and the man does the same. Thinking themselves wise, they became fools. This is why evolution was demonic and homosexuality has grown exponentially since. Because we won't accept the Bible as written, we try to fit scientific theories into the Biblical stories.
The Word of God is either true or it isn't. God can either speak something into existence or He can't. We are told there is nothing too hard for God, but then we start mixing billions of years into Genesis. God calls this unbelief. You can't please God without faith.
These people that say God is a genocidal maniac just don't understand that He is killing evil people. The SJW people believe everyone is the same. They are not. God spent most of the Bible electing and separating His people out of the world. As a Gentile, our job is to be adopted into Israel as Manasseh and Ephraim were. The only way to do that is to accept the Blood of Jesus to be saved. Joseph was a type and shadow of Jesus and married a Gentile bride from Egypt (the world).
Well and truly written.