My understanding of his position is that he does not consider firmware to be independent software. The arguments by which he came to be in favor of free software do not apply to firmware.
The reason that he promotes free software is because software is capable of being free, that is, it is logistically realistic that people freely copy, modify, and distribute it. From this, he extrapolates that there is a right to copy, modify, and distribute software. If would be physically capable of modifying the code, but is legally prevented, then that is a restriction on his rights.
Under his reasoning, it also does not apply to firmware. Because it is so tied to the underlying hardware, it's not really possible to copy or modify it in any useful way. It is certainly free, in the monetary sense, but there are no useful results of doing so. Therefore, closed software does not restrict your rights in a meaningful or non-trivial sense.
Note that this is just my interpretation of what I've read of him, and I don't follow the Free Software thing that closely so I could be mis-interpreting key points.
> Because it is so tied to the underlying hardware
Firmware has changed over the years, as have the devices we embed it into. Thee devices are much more complex and capable, sometimes, smarter than the computers they connect to. I have worked with devices that ran MS-DOS-like OSs and applications on 386-class processors with built-in printers running a real-time Unix-like OS on a 32-bit RISC processor.
Also, many different devices share common hardware and designs. Hundreds of routers and other various networking devices currently run OpenWRT firmware instead of their original software. Those little boxes are smarter than the first Unix machines I used and at least an order of magnitude smarter than the Burroughs B-500 mainframe that ran land taxes for a whole city on my first internship. All it lacks is a line printer and tape drives.
Isn't the whole point of his choosing that particular laptop that it has Free firmware as well? Similarly, he chooses to use gNewSense because it doesn't include any firmware blobs or similar. That suggests to me that firmware is also something he cares about - because if you run Free software on top of a non-Free firmware, it is possible that the firmware could undermine your freedom - for example, a firmware update might remove the ability for you to install other operating systems.
The reason that he promotes free software is because software is capable of being free, that is, it is logistically realistic that people freely copy, modify, and distribute it. From this, he extrapolates that there is a right to copy, modify, and distribute software. If would be physically capable of modifying the code, but is legally prevented, then that is a restriction on his rights.
Under his reasoning, it also does not apply to firmware. Because it is so tied to the underlying hardware, it's not really possible to copy or modify it in any useful way. It is certainly free, in the monetary sense, but there are no useful results of doing so. Therefore, closed software does not restrict your rights in a meaningful or non-trivial sense.
Note that this is just my interpretation of what I've read of him, and I don't follow the Free Software thing that closely so I could be mis-interpreting key points.