In the case of egoism, the arguments against it typically try to imagine some sort of scenario where failing to follow non-egoist principles results in some sort of morally disgusting result. This type of argument is fairly common in ethical reasoning, as well as any other field where you’re prefer to not reason from first principles. But it’s a type of arguments that, by its design, fails to even notice that there may be some positive argument for the principle in question. In fact, the argument type I mention really just results in begging the question, as the “morally disgusting result” is typically evaluable as morally disgusting from non-egoist principles. One rarely comes across an anti-egoism argument that actually engages the egoist argument on egoist terms. Anti-egoists, like anti-Darwinian, prefer to stay within their own premises and then show that, by golly, you can’t be both a creationist and a Darwinian, so Darwinism must go (you can’t be both an anti-egoist and an egoist, so egoism must go).

As it turns out, there isn’t a coherent alternative to either neo-darwinism or ethical egoism. Additionally, neither evolution or ethical egoism result in morally disgusting situations. Evolution, so far, results in humanity, among other things. Ethical egoism, as I live it, is full of creativity, co-operation, compassion, and love.

I suppose that if it were true that ethical egoism required me to violently subjugate every person I encountered and that I could only feel true happiness when sunbathing by the side of a river of human blood…well, I would probably reconsider ethical egoism. In this vein, if everyone shit ice cream, then restrooms would be restaurants. But, as things actually stand, ethical egoism has made me a decent person and nobody is eating out of their toilet.

None of those have a whole lot to do with animal welfare, so they’re not relevant here. But two subcultures, Objectivists and American Conservatives, are both proudly anti-animal welfare, at least in some sense. Neither embraces animal cruelty as most people would understand that phrase, but both could consider eating a steak to be a political act against hippies who think animals should have rights.

I don’t believe in animal rights. Animals are not political. I won’t go into this too deeply, but I will just say that Ayn Rand’s derivation of rights is the one I find most convincing, and it doesn’t apply to non-conceptual beings. And that’s where I’ve stood for a long time in relation to animal welfare.

But I am not much for politics in general and I certainly don’t care to use political ideas to make personal decisions. Rights are useful for constructing societies, but when I’m choosing among possible actions rights are under-determinative or irrelevant.

Simply, I have an animal in my family. We have a dog named Robot and I am unable to feel the way I do about him without also caring about the welfare of animals like him. That means when I eat, it matters to me that the cow that gave the milk in my food did not suffer in so giving. It matters that the meat I eat did not come from a sick animal, rotting in what is effectively a cell.
Further, it matters to me that I not eat meat or drink milk at all. But that isn’t the only thing that matters to me. I try to live a happy life and suddenly changing almost every dish in my diet is not likely to make me happy. I’ve spent the last 28 or so years learning the foods I like to eat and I doubt I could find vegan meals to replace all those dishes very quickly. Living a vegan life is a factor in my eating decisions, but it is not the only factor. These days I try to eat new vegan meals pretty regularly, but I almost never have only vegan meals for a whole day. I’m walking, not running, to veganism. I expect to get there, but I’m not in a rush. It’s hard for me to rush and be happy at the same time.

I’m an egoist, so animal suffering doesn’t count for everything. In fact, human suffering doesn’t count for everything, either. But they both count for something, at least to me.