Because he did what he did even though he knew it was bad to do what he did, and now he is telling us what is the right thing to do. It is clearly described in

Because he did what he did even though he knew it was bad to do what he did, and now he is telling us what is the right thing to do. It is clearly described in the article! What is not clear is if what he is telling us now is the really right thing to do, or if in 30 years time (he'll be just 120!), he will tell us what it is that we really should be doing.