Per my framework above there is every incentive for the robots to paint a thorough narrative to compel the hero-matrix population, even though it's as real as the stuffed rabbit that greyhound races use to compel the dogs forward.

A similar thread runs through the plot of the original Total Recall, the struggle is very real to the participant but everything is happening in accordance with a scripted framework. The difference here is that it's multiplayer and intended as a stationary generational ship until there's a biosphere for the contents of the pods to run around in again. Even if Zion really was the outside world, cracking open all the pods would simply ensure the extinction of humanity as there would never be enough single cell slop or untainted air or barely survival living on stress and anxiety to go around and Zion would fill to the top with human blood.

Humans were entirely dependent on these machines for the basic continuation of human culture on top of basic human survival, and we have the gall to feel more comfortable seeing them as the enemy than actually embracing the depths of our guilt. Knowing how badly we screwed up would destroy the culture that the pods are attempting to preserve, so the machines just play pretend bad guy to keep us busy. Like a cat attacking a laser to stay entertained.

Liars often say they can't or won't lie. It's part of the technique known as lying.