Sounds like he is basically saying Bitcoin is broken and that Gox should have implemented their own way to find out if a transaction is real or not. I hate to say it but if a flaw like that really does exist how can one say it's not broken.
Well imagine you pay a plumber $100 dollars with a check and a week later he says he lost the check and wants another one. What would you do??
If your answer is that you would write the plumber another check for $100 without thoroughly checking with the bank first, then you would be like Mt Gox.
They are stupid beyond belief.
That is a good analogy. So basically Mt. Gox was supposed to but did not implement in their wallet software a way to verify the funds in that transaction.