Why isn't there support for all versions of the game yet, including "Chronicles"?

For the Chronicles, you'll have to "slightly modify" dependencies in 340,000 lines of code and debug all of it. Just because Chronicles is a cut-down version of the third game doesn't mean that to create an HD mod for it, you simply need to take an existing HD mod and trim it; it doesn't work that way.
This was done by one person, and it's not paid work, so demanding anything is completely inappropriate. Besides, this functionality is only needed by a very small group of people relative to the online community for the third game. Moreover, alternative solutions to the problem have already been suggested.