He's basically claiming that if the blocks ever fill up, then Bitcoin has failed.
I have always suspected this guy is a clueless zombie. Quite the opposite, filled up blocks is not a failure but success! Economy is always about supply and demand. Success of a product or service you are offering is measured by how much demand is surpassing supply.
The point is that the blocksize cap forbids that supply grows to cater the demand for transactions. The real question is: will we allow market forces to determine the size of blocks, or do we apply central regulation to limit the size of blocks? The reason that I sometimes refer to the Core devs to the Polit Bureau is that they advocate central planning. Which I believe is the wrong approach. It is leading to transaction queues (in the mempool), just like it led to queues in front of shops with limited stock in communist countries.