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.