If you read between the lines, he's basically saying that they did not have complete design and certification criteria for this feature of their aircraft and that that's ultimately at fault. In other words the MCAS met the design criteria established by the systems engineers, and the AoA sensor met the design criteria established by the systems engineers. And it passed all of the system-level testing established for the plane. It's just that the design criteria didn't include statements describing the AoA sensor data as being critical for the MCAS to function effectively.

And as a result nobody analyzed the software design to determine whether a fault in the AoA sensor could cause the MCAS to perform in a state inconsistent with aerodynamics. And nobody who was working on the AoA readout was aware that the AoA sensor fault indicator would also indicate a problem with MCAS. What he's strongly implying is that this was a mistake on Boeing's part.

However what he can't do is come out and say "I'm sorry guys. We fucked up. Our systems people failed to fully and properly account for this new system in the design criteria and as a result we failed to dedicate enough engineering resources to ensuring that faulty sensor inputs to this system couldn't result in a crash."