So it's "worship me or I kill you and you'll burn in hell!"
Isn't that exactly like the abusive husband that tells his wife he'll kill her if she leaves (is against) him?
We don't put up with that kind of behavior in society, why would we put up with it in religion? Give a strong NO! to your god and go to a shelter (aka education).
Luckily, more and more people are doing that in record numbers every day.
Furthermore, with the flood he destroyed almost everyone, so he either thought everyone was against him wich is stupid because probably 90% of people didnt even know he existed (if he did) or he just likes to kill people.
...or HE DOESNT EXIST.
The flood happened around 1,600 years after the creation. Everyone knew about God from their ancestors. They simply ignored Him, same thing that is going on today.
God reads the hearts of all people. They are easier for Him to read that an open book. The wickedness of the people revolved not only around their denial of God, but it included all the different ways that people can harm each other. In fact, because the earth was much newer than it is now, the people (who often lived hundreds of years) could think a lot better than we can think now. They probably developed methods for doing wickedness that we can't even imagine.
God made people. He doesn't want them to be destroyed. But, since He is a giving God (look at all the good things He gives to people), finally He will give wicked people what they ask for... the results of their wickedness... destruction.
Regarding what is going on today, Jesus mentioned a list of things that would happen at the time in which He returned. One of the things He said was:
“Therefore keep watch, because you do not know on what day your Lord will come. But understand this: If the owner of the house had known at what time of night the thief was coming, he would have kept watch and would not have let his house be broken into. So you also must be ready, because the Son of Man will come at an hour when you do not expect him.