An unusual Ending

Today, I finally finished the book "Cat's Cradle". This is a book I've been reading for over 2~3 months. Let me first briefly talk about this book. This book is full of satire. It is exaggerating today's society, religious and our life style. This book talk about the selfness of scientists, poverty and lies in religious for the most part. The main character, John is in a island, a third world country with ridicules rules and religion. He is with a bunch of other characters and they are experiencing a major change in that country. The president of the country is very sick, and he is about to die. However, the man he chose to rule the country doesn't want to take the job. He is called frank, a scientist who caries the most powerful weapon in the world, ice-nine. Eventually, John got the job because he wanted power and a woman which he love. After taking the job, he become more arrogant. After taking the job, the old president took a little drip of ice-nine and killed himself. The effect of this deadly weapon shocked him and made him nervous. This is when the author tried to explain what science is doing to our world and how easily an individual could change his/her personality from power.
Eventually, an accident happened, and the ice-nine got into the ocean and freezed the world. Storm started occurring all around the world. Fortunately, John and her beautiful wife survived by hiding in a underground shelter until the storm dies off. During those time, he and his wife had a lot of furious sexual orgy. I believe the author is trying to predict how the judgment day would be like, sexual orgy.
Afterward, John found out what have he done making this world into this huge disaster, and started regretting. He started learning from the natural. While he is trying to survive, he met another major character in the book, Bokonon. He was the creator of the country's religion. The religion is based on one thing and one thing only, LIE. Bokonon figured that the world is full of lies and there will never be an utopia. And when John met him, Bokonon was writing the last sentence for his book, his religious book. It was "If I were a younger man, I would write a history human stupidity; and I would climb to the top of Mount McCabe and lie down on my back with my history for a pillow; and I would take from the ground some of th blue-white poison that makes statues of men; and I would make a statue of myself, lying on my back, grinning horribly, and thumbing my nose at You Know Who"
This is very power sentence. It described the main theme of the story, human stupidity. It says if someone is able to record all the stupid things that human did, the pages will pile all the way up and be as tall as mountains. However, I don't quite get the "grinning horribly" part. It could mean the regret from human or the curse to God. What ever it is, it is always going to be an enigma, and there will never be a real answer for that rhetorical question.