In 11:9 after the story of the Tower of Babel, it says "from there Hashem scattered them throughout the land".
Rashi compares the Generation of the Flood to the Generation of the Tower of Babel. he concludes that despite the Babel people being evil, because they rebelled against God, they were not as bad as the Flood people. Rashi comes to this conclusion because the Flood people were destroyed while the Babel people were only scattered. From this Rashi learns that dissent and dispute is worse because the Tower people had peace with each other and that is what saved them.
I would like to add that dispute with fellow man is much worse than rebelling against God. This is similar to our concept of repentance. If one commits sins against God, he can repent and request,, and receive, forgiveness. But when he sins against his fellow man, we know that it is much more difficult to receive that forgiveness.
One must be extremely careful in his dealings with other people.