You might want to check a different translation. CJB says thus:
Adonai said, “I will wipe out humankind, whom I have created, from the whole earth; and not only human beings, but animals, creeping things and birds in the air; for I regret that I ever made them.” - Genesis 6:7
Verse 5 states why God is regretful: "Adonai saw that the people on earth were very wicked, that all the imaginings of their hearts were always of evil only." It is because of people's willingness to believe Satan's lies and rebel against God. God planned to wipe all creation off Earth, but Noah proved to God that humans can indeed be good, even in corruption and death.
btw i feel this a good time to remind you guys that sea of thieves was made by rare, who also made DKC1-3 and DK64, alongside banjo kazooie and conker's bad fur day