Contrary to the title, it looks like Barnes & Nobles did release some sort of source code. The fact that the author wasn't able to compile them into something doesn't mean BN is violating the GPL. I'd cool down before making such accusations.
Based on some of the screenshots, it might just be the case that the author doesn't know how to upload the kernel to the Nook correctly.
Moreover -- correct me if I'm wrong -- GPLv2 doesn't require that the device manufacturer support software upgrades anyway. It's only v3 that introduced the "anti-TiVoization" clause, and the kernel isn't GPLv3.
AdamOutler is not one that would have trouble uploading source code to the device. He's saying that it's not compilable. There are other threads and statements saying there are missing components from the source release.
