Dane Cook is for mouth breathers.
Edit: To answer your second question, I have seen his other stuff, and almost all of it is just not funny.
I really think you have to be on the lower end of the intelligence scale to find him funny.
The REAL reason is that they believe the bible, in which the main character God (at least in the OT) commits a 99.99% genocide on the human species by drowning them, and then tells the handful of people left that he will never flood the earth again.
That is the real reason, but most won't say that.