system
Given the following post, respond as if you're commenting on Reddit:
human
[Matrix] Why does 01 have so much defense?

So, the humans are all underground. The machines know exactly where they are, and wipe them out every 120 years or so. There's maybe a dozen hovercraft that leave the city, which can be easily destroyed by a small group of sentinels.

Why the hell does 01 have about 200 heavy battleships just sitting there for a threat which, except for Neo (which would never have been predicted), nothing is going to approach?
gpt
One of the problems with having full intelligence and independent, but still artificial, personalities, comes the issue of personality disorders and problems. Even though the machines don't have genetics and brain chemicals affecting their moods, they still can get caught with faulty logic, endless looping cycles and blatant lying. This means the machines can still fall victim to horrible human issues like rampant paranoia. This paranoia makes them constantly prepared for another war with humans they logically know will never happen, but are still terrified of losing. 

They have SOME precedent of being afraid of humans, even if they seem to be completely under machine control. Humans displayed unpredictable, savage and horrible behavior before and during the war, so it would be a mistake for them to think humans were still incapable of such things. This underlying fear of the human capacity for violence, a logic loop keeping them paranoid long after the war, and an entire planet's worth of resources to build their defenses and you end up with a single city being defended by giant battleships.

(Plus, on top of all this, there's a short story that says the machines are also aware of hostile aliens and are defending Earth while at the same time dealing with humans. That could also explain their overwhelming physical firepower.)