Digital imagers are a different media than analog silver halide, so a different ISO standard applies. As a matter of fact, the number of ISO standards that apply to digital imaging is absolutely massive, covering the full breadth and scope from design to use to storage of the digital media.
It's a fallacy to say that a digital sensor has a single sensitivity: There is no functional equivalent to traditional analog sensitivity in the digital world. Rather, the output of a digital camera is a function of the Spectral Quantum Efficiency, Fill Factor, Well Capacity and the exposure time (more correctly the integration time), dark current, Bayerian filter recombination schema for color sensors, analog gain setting, Bit depth of the A to D converter, and finally the digital gain setting. Of these, the only real analogous equivalent to film photography is exposure time. The other parameters are dependent either on the physical properties of the silicon detector or on the design of the FPA and ROIC itself (not to mention the post-processing which occurs downstream of the digital gain stage on the output of the A2D). That said, when you really want to geek out about the physics of the processes, Quantum Efficiency was often compared in the early days....but QE has to be redefined for analog as the efficiency of the conversion of photons to developing centers on the grain. Put another way, that process wasn't widely known as "QE" before digital imaging came about. See
http://www.imaging.org/site/PDFS/Papers/1998/PICS-0-43/622.pdf for one of the earliest examples.
Analog and digital imaging are almost entirely two different animals, the functioning of which are about as closely related as film photography and oil painting. All three of these media mentioned produce an image in entirely unrelated ways, but the end result -- an image observable with your eyes -- are equivalent (if the oil painter is a realist).
Rather than fall into the trap of analogies between the two media, you really have to consider the digital Focal Plane Array as an entirely different type of imaging system. Blame the early producers of digital cameras for the common practice of trying to compare the two media directly. Looking back to the days before digital photography hit the scene (i.e. the 1980s and 1990s), users of digital imaging systems evaluated the performance of those sensors in terms that made sense to the capture of an image through the photovoltaic effect rather than silver halide. However, discussing the capabilities of the digital camera in terms which make sense to those users -- who lie outside of the realm of consumer / commercial photography -- would have left film photographers unable to appreciate the benefits of the digital cameras that manufacturers were hoping to sell in the early 2000s.
So either independently or in conjunction, all those parameters that affect the digital output aside from exposure time were rolled up into a single sensitivity value equivalent to film's ISO rating, the high equivalent numbers of which were then (conveniently ignoring the very important SNR values) touted as a significant benefit to using digital imaging. Having been a digital imaging user and designer outside of the realm of consumer photography at the time, I watched this comparison of ISO rating spring up and establish itself in the consumer photographic market. Its use is unique to this particular digital imaging market. Satellite imaging systems, for example, have no ISO rating listed in their detailed engineering / user performance specification nor even in management power point presentation because it is misleading in understanding the true sensitivity and performance of the imager.
So from that perspective, what the guy is saying is sensible. However, that sort of rationalization is only one factor in defining the terms that a specialized community adopts. Simplicity in understanding, rules of thumb, and tradition have as much or more to do with terminology as anything else. Very few photographers will recognize the meaning of the term Double Gauss, but we all know what a 50mm lens is (they are both the same thing, almost without exception).
