you misunderstood what they mean. they do not mean that the livestock grow instead of your main species either by natural growth or in clone vats. they mean that the livestock push you closer to the pop growth limit and therefore increase the cost of every pop going forward. livestock or not, a pop is a pop in terms of the empire wide growth limit.
No, I got that, it's just a bad objection. The empire growth curve is nowhere near so steep that you'd be better not capturing the livestock-pops, and there is no meaningful opportunity cost. You are always better with the pops than without,
especially when you're the primary type of empire that actually uses them, ie Gestalts.
There's no point in the game where capturing livestock isn't a net positive in capturing them. In the early game, livestock free up your limited drone pops who would be farming for pop-upkeep to do something else. In mid-game, livestock work towards your clone vat buildings as you go towards bio-ascension. In the late-game, once ascended you can change them into drones, unless you're a machine-gestalt who just uses them as a drop in the energy mountain requirement. But they're always a net plus.
And that's the crux, because the objection of 'livestock is a bad job' is misses the fact that gestalts are limited in their ability to use pops by design, not accident, for the same reasons of balance that genocidals are. The alternative to 'lives stock jobs' for a gestalt on the fundamental design concept level isn't 'ok, they can be used as any menial laborer', it's either 'why do you think they have a role in the hive at all?' or 'ok, how far do you want to nerf it?'
Gestalts by design and balance get considerable early game pop-economy advantage (growth + assembly for Hives, 100% habitability robot assembly for machines) early-game war-making advantage (no consumer goods and double the early alloy productio), and early expansion/claim advantages (increased base influence). It is relatively trivial for Gestalts- even the maligned Necro-hive not running a food deficit catalytic economy- to get overwhelming alloy economies by year 30 to swarm their neighbors with corvettes. They aren't necessarily the best for blitzing, but they are more than strong enough to start conquering in the Corvette age rather than waiting for Cruisers.
The trade-off for this extremely powerful early-game war potential, just like other examples with better-than-fanatic-militarist early war bonuses, is limited ability to make direct use of pops that are captured. It is, at a balance level, the same balance consideration as genocidals. Thematically genocidals kill pops because that's what they do, but on the mechanical level genocidals kill pops because if they didn't they'd be ridiculous OP snowballers.
Because Gestalts can trivially double the alloy production of the vast majority of empires in the game, the fundamental balance philosophy for how they can make use of pops is never going to be 'ok, we'll make your early conquest advantage more rewarding by letting you do as you please with these pops.' It has always, and will only, limit what you can do with those pops.
Livestock are not interchangable pops who would be another drone if this job didn't exist. Livestock are what you get instead of purging, which is the typical conceit for most playstyles with this much early war potential.
