The author is interviewed on the latest "Thinking Atheist" podcast if you're interested.
The thing is, at what point is someone 'too far gone'?
Ignorant of critical thinking etc is one thing, but when you also have a very high level of arrogance and intellectual dishonesty it seems like nothing works - and the best you can do is at least try and stop the person from influencing other susecptable persons.
Is there a point where someone is too far deluded/arrogant?