StingingVelvet: This is getting too far into semantic minutiae territory for me, no offense. As long as GOG provides a way to install and play your games on a new system without contacting a server they have lived up to their promise, IMO.
Ok, so now it is clear what you expect from them. I have already seen that for many others the idea that we would have to download our GOG game installers with Galaxy (no option to use a web browser instead) is breaking the promise of a client (Galaxy) being optional.
I guess their thinking is that Galaxy being optional means they never have to install nor use Galaxy, even for downloading the standalone offline installers. While I can understand that argument, I personally still would be fine with an official client that you need to use for downloads, as long as it does its job well. If I understood you right, you would be fine with such an approach as well (Galaxy required to download the offline installers), or at least you'd feel GOG hasn't broken its promise of the client being optional then.
The next step from that would be like how the DRM-free games in Steam are handled, ie. you have to download and install the game once with the client (Steam)... but after that you can zip the installed game files to make a compressed package that you can copy to another PC and play there even without the Steam client (maybe needing to install dependencies like DirectX9 or Visual C++ 2005 separately, as they wouldn't be included in those zip files). Would people still consider Galaxy optional, if it required one to download the game files and install them the first time, but after that they could use those game files independently? For those who feel "Galaxy is optional" means "I never have to even touch Galaxy, ever", I guess not.