Don't be too dismissive; he is honest, writes well, and at least has the "business sense" to make an honest public resignation to fate. A calculated show of weakness is strength, specially in a commercial entity.
You have too much emotional bonding with your project at that stage to see clearly.
The problem is that plenty of people will isolate themselves from criticism and actively reaffirm their connections with people that tell them what they want to hear (if only because they don't want to lose their friendship).
Giving up on ideas that don't fly is probably an integral part of every successful entrepreneur.
Just like successful VCs will turn down almost all of the 'maybes' in order to be able to concentrate on the winners. Why go after the high hanging fruits first ? It simply makes no business sense.
As others have pointed out, being able to give up on an idea that won't fly is part of being an entrepreneur.