The old Commandant was the founder of the penal colony and the designer of the apparatus. According to the officer, he was kind of the bomb. He was responsible for everything about the colony, from the sentences of the apparatus to the operation of the judicial procedure. He was "soldier, judge, mechanic, chemist, and draughtsman" (10). Nobody would dare disobey him. Plus he had "ladies."
A sort of aura surrounds the old Commandant, at least when listening to the officer talk about him. It's as if he's God or something. He's a Creator: the colony is all his design, just as he built the machine himself. Oh, and don't forget that everything he made is perfect (according to the officer). The old Commandant is like a divine Judge or Lawgiver: his system delivers perfect justice, which everybody knows is just (or so the officer says). And he's kind of like Jesus: apparently, there's a prophecy that the old Commandant will "rise again" from his grave and lead his faithful to retake the colony. Though most people in the colony now find this notion very funny.
How you see the old Commandant depends on how you want to read the story. Is he something of a mythical figure or even an allegory for God? If he is, then everybody's laughing at him amounts to a "loss of faith." Or was he an extremely sadistic, power-hungry guy, who the officer makes the mistake of worshipping as God? In which case, the officer's reverence for him is kind of tragic.