Like most people, I beat it on easy when I first got it (at the age of... 7, maybe?)
Skipped medium, went straight for hard around 2 years ago. Even if the difficulty is mostly of the cheap, unfair AI advantage, I had fun and felt challenged doing it (particularly Plymouth, because.... spiders do not replace combat units -_- Nor do supernova panthers and tigers for that matter.) Must be just how attached I am to the game.
So yes, Zhall, you pretty much are the only one
Go fix it