I do indeed agree that by not releasing the key, I am leveraging NVidia's hardware DRM for my software.
I don't agree that Rei's implementing a form of DRM -- I do not think that "not releasing the source to your software" is DRM. I'll note this point is debatable, but that's my stance.
I have two points in this thread, I think:
1. Sept is free and open source software under the GPLv2, as it is fully compliant with all terms of that free/OSS license.
2. People are welcome to feel like sept deserves criticism, given the hardware DRM it leverages. People may also feel like DeltaLaunch deserves criticism, because it is now closed-source. However, these are two different things to criticize for, and not comparable -- someone could very legitimately want to criticize sept but not think DeltaLaunch is doing anything wrong, and someone could very legitimately want to criticize DeltaLaunch but not think sept is doing anything wrong.
My personal stance is that neither are doing anything wrong -- I think closed-source software is worse for everybody involved than open source software, particularly in a scene like this, but as the sole author and copyright holder it's Rei's decision to have his software be open-source or not and he's not actually doing anything wrong by choosing closed-source.