I don't know, I don't think Hudson and Walters really believe the crap they're saying. I think they're just toeing the company line because they have to. I mean, there's a point where it stops being stubbornness and becomes denial.
But you have to keep in mind that this was their
ending, they may have been forced to rush certain elements of it but they thought that the star child, the organic/synthetic conflict, synthesis, the destruction of the relays, and the crash on the jungle planet were the best way to end the story. There's a whole host of problems in that last ten minutes and they either didn't notice them or they didn't feel the need to address them. There's no reason to believe that they're capable or willing to see those problems now.
That being said, I remain optimistic that the extended cut will be "good enough".