There are alot of people who seems to be under the conviction that Carlsen did this as a way of avoiding the WC cycle to get a shot for himself. I have a question to everyone in the thread who expressed that, and similar opinions.
What giant crack pipe have you been smoking?
The fact that you/we are all talking about the letter helps to demonstrate the point that Carlsen is immensely popular, he's certainly holding the attention of the folks on this forum and elsewhere.
He does hold attention as a very strong chess player, however his philosophical ideas don't rise above what could be expected from his age.