In case you were unaware, the source code of the original is included along with the re-release in this repository, as stated in the first sentence of the readme.
I think Zambyte just wanted to let the GP know that the code for the original had already been released before this one. No need to be mean.
It's also only the code for the game.dll, which is important for modding but doesn't include the new engine.
If it's anything like the Quake re-release, it's not actually using idTech 2 at all.
In case you were unaware, this is actually the source code of the rerelease of Quake II. The source code for the original Quake II has been released for many years[0], along with many of the id Software classics[1].
[0]: https://github.com/id-Software/Quake-2
[1]: https://github.com/id-Software