> If one doesn't find this book useful, they're under no obligation to use it. And the author isn't likely to change his position based on a few grouchy Internet commentators.

Yes this is what I don't understand. Why are there so many critical posts about this particular decision? Why didn't those users just close their browser tab and move on with life? They are bring offered a free resource, it doesn't meet their needs/desires, they choose to complain. It seems very rude to me. The few who have suggested alternatives are contributing.