[deontologizt]

This is a great reductio ad absurdum of utilitarianism. However, I find it very worrying that the so-called "effective altruism" movement takes this kind of thing seriously. Look up the EA-affiliated "Foundational Research Institute" -- it's an entire pseudo think tank whose philosophy is based on negative utilitarianism, the idea that all that matters is minimizing suffering, and we should do so by any means necessary (not excluding the extinction of all life). There are other organizations that support habitat destruction on utilitarian grounds, such as "Sentience Politics" and "Animal Ethics", but FRI is the brains of the operation, so to speak. (Animal Ethics is the propaganda wing, and Sentience Politics is trying to make it policy.) Brian Tomasik, who is cited in the OP, is the founder of FRI and has written a lot about "wild animal suffering" on his blog. His conclusions are very counter-intuitive; for example, he thinks forest fires are good because they reduce the number of suffering animals in existence. That said, his articles on the possibility of sentience in reinforcement learning algorithms are pretty interesting!

[antisthenes]

This can't possibly have anything to do with utilitarianism as it is impossible for us to understand domesticated animal utility preference curves beyond "being fed and warm = good". If one is being pedantic, I'm sure one could find many wild species which fare will in confinement, and make a case that it is cruel to contain wild animals in cases where utility from our entertainment does not outweigh their dis-utility from being imprisoned (such as zoos). I'm not convinced that such an argument could be made for domesticated or feral animals.

Utilitarianism is primarily about maximizing utility of a wide spectrum of the population as it pertains to humans and societies and has nothing to do with animals, wild or domestic except for the utility they provide humanity with.

Negative utilitarianism separated from the general concept of utilitarianism is, of course, a nonsense concept in and of itself, since its end goal is non-existence, which makes utility unable to exist.

I'm not familiar with other pseudo-think tanks, so I'll defer to you on that one.

[deontologizt]

> Utilitarianism is primarily about maximizing utility of a wide spectrum of the population as it pertains to humans and societies and has nothing to do with animals, wild or domestic except for the utility they provide humanity with.

Actually, utilitarianism is about maximizing the welfare (i.e., happiness minus suffering) of all beings that can be said to have a "welfare". This goes back to the father of utilitarianism, Jeremy Bentham, who argued that any being capable of suffering deserves moral consideration. (more extensive discussion can be found in https://en.wikipedia.org/wiki/Utilitarianism) More recently, the most prominent living utilitarian philosopher is Peter Singer, who has argued extensively for the moral consideration of animals. Utilitarianism in the philosophical sense is distinct from the anthropocentric economic interpretation.