The Matrix is often criticised for its weak central premise - humans do not make any better a source of fuel than, for instance, plants. but what I think is implicit in The Matrix is what is explicit in the movie it is widely recognised as being heavily inspired by, Dark City, in which the malevolent aliens controlling the city need to study humans specifically because the humans have something the aliens don’t have but need. I think it’s clear by English’s employment of computer beds and (spy-)drones that the situation on Alternia is the same. English needs the trolls to make a new universe for him the exact same way drones need a population of living trolls to make more drones - at least until the Condesce has the technology to do all that with machines.

maybe the drones lacking genetic material is an analogy for something else - or maybe it’s exactly that literal. maybe the reason Lord English needs a race like the trolls to reproduce for him is exactly because by disposing of his female half he made himself totally incapable of sexually reproducing himself!

(how’s that for an obvious thing I missed: by throwing off his “creative” female side, Caliborn condemns himself to be literally unable to “create” in any capacity)