Ok, granted that's true but where does it state that when anything other than a PC rises in HD it gets a feat?
A Feat, as per PHB is gained when advancing in character level not HD, the glossary defines HD as "a measure of relative power is synonymous with character level
for the sake of spells, magic items and magical effects that affect a certain number of hit dice of creatures"
While looking this up i think i found the passage upon which this is based, basically:
Although most of this paragraph (Monsters as Races) seems to be intending that there is at least 1 class level present it doen't literally mention this.
So i suppose it could work for the Psicrystal strictly RAW...
EDIT: calling people anal because they ask an explanation to iffy rulings is not nice