I don't think it's a best example. MMAcevedo is about running a real human mind on a different substrate (for science, for labor, or to torture it for fun a million times, I guess, by a bored teenager who got the image from torrents).

Scaling up these neuron cultures is rather something like "head cheese" from Greg Egan's "Rifters" novels (artificial "brains" trained to do network filtering, anti-malware combat etc.).

I had a genuine feeling of dread reading that, wow.

For me the issue isn't with the killing/eating of animals. Rather, it's how they are treated during their lifetime by the meat industry - which is essentially optimizing for the minimum conditions that can still provide meat that can be sold legally. I'm not a vegan by the way, but I can appreciate the moral case vegans make.

For the same reason that we now consider murder, assault and other actions that harm people morally wrong. These have also been a part of life ever since humans or other hominids roamed the earth, we just determined that they are morally wrong later on.