I think that these Goblins have been 'domesticated' by the Cult of the Absolute to be useful. This is clearly an orderly, well run and far-reaching organization that utilizes the strengths of all involved. Goblins are numerous but disorderly. Enforce discipline via Hobgoblins and you can build up a decently sized and useful force of expendable foot soldiers with very little cost. We know that the higher-ups in the cult are called True Souls, True Souls have a mind flayer tadpole in their head, the Hobgoblin in charge of the goblinoids of the fort has a tadpole, like us the party. The Hobgoblin is a 'True Soul' and is using his new powers to rally all the goblins, wargs, bugbears, and whatever else nearby into an army. They also have some dealings with the Drow, as seen with Swen when he played a Drow, the goblin toying with the Deep Gnome showed him deference and another goblin drunkenly mentioned the 'look on the face of the duke when we handed him to the drow'. The deep gnomes friend who disappeared found his friend's amulet on a thug in Baldur's Gate. The goblins were ordered to bring the gnome back (after teaching him to fly) and weren't just being sadistic for fun. The goblins are being organized and influenced by a more 'civilized' race to be useful. Cheaper and less obvious than summoning fiends or raising armies of the dead.
