He thinks that diffraction is caused by photons being attracted to the aperture blades, interacting with the electrons of the atoms of the material making up the aperture. Unsurprisingly, he says that scientists don't really understand this bit. That would be because it's wrong.
When I first learned to drive a car behind the iron curtain, one part of the course and exam was a technical section where we had learn and demonstrate knowledge of the internal combustion engines, including ignition, coil, carburetor for 2 stroke, 4 stroke and diesel cars. Surprisingly, most westerners didn't have a clue about these things. But they knew how to start the engine, press a brake, and pilot the car to the nearest fast food restaurant or to a drive-in movie theatre.
Similarly, most photographers don't need to know the characteristics of the photons passing through the shutter and arriving on the sensor, all they need to know is that smaller aperture results in the loss of absolute sharpness (and in some cases also in appearance of dust spots, primarily in the sky). And that was the main lesson Tony was trying to impart to his subscribers.
