Because vanilla Generals isn't good enough for you. Realism overhauls and graphical enhancements are the main points of existence of this mod. If you want tons of new units, this is not the mod for you.
A video response to this poll: Moddb.com
I've already made a choice though. All water will be available for the users to choose for themselves since it doesn't affect the game matching system and performance and some people might want to choose the optional ones.
The song is "Overfly" by Haruna Luna.
For youtube version, here: Youtube.com