It's not retarded, like you said, there are a number of rights licensing problems with the track, especially given that the artists who produced that track are all separated. I believe that GBX did attempt to include it, but the people who own the track now did not want it included.

There's a mod (that probably doesn't work on 2.1) that adds the track back in, but there is no chance of the track being included unless the people who own the track allow it. The track, as i recall, was specifically made for the original Homeworld release and wasn't intended to be reused beyond HW1 Classic.