The images you share are of factory farming that is indeed an atrocity that must be eliminated. There is no justification for treating animals like this.

However, my question was "why is it immoral to eat another animal"? Are you perhaps suggesting that the only way to eat another animal is by causing the extreme suffering undergone by cows in American factory farms?

It should be obvious that this is not the case: people eat meat all over the world, but American factory farms exist only in the Americas and farming in other places does not involve the kind of extreme suffering that you point out. For example, most of the meat I eat is from sheep and goats that graze freely in meadows and hills around the place where I live, in the Eastern Mediterrannean. I know that is true because I see those animals everytime I go out. Some goats live in the farm I'm staying and I can assure you that they are not suffering one bit.

In general, the animals raised by small-scale farmers, in herds of no more than a few dozen animals, are amonng the happiest, healthiest, best fed, best cared for animals the world over, some even better cared than human infants.

Bottom line, it is perfectly possible to eat meat without causing the extreme suffering you are concerned about. To be clear, I absolutely agree with you that causing extreme suffering, of the kind in the video you shared, or of any kind at all, is absolutely morally repugnant. But this extreme suffering is characteristic of factory farmign, not of eating another animal, and so I am not satisfied that I understand why you think that it is immoral to eat another animal.

Edit: I keep rewriting the above to make myself more clear, but everytime I read it, it sounds like something from a high school debate. What I really want to achieve is to understand how you think and maybe help you understand how I think, if that's interesting to you at all. So if something I say sounds completey wrong to you, please let me know and I'll try to make it more clear. I am not looking to score points in a futile internet fight. I'll be happy if we can find some common ground- and I can see that we already have some: I think we're both disgusted by the horrors in the video you shared.