I generally avoid arguing with people who are already doing what I'd prefer they do. But I do find this point interesting.
Try framing the argument this way:
Omega lets you save one human life, but doing so requires you to create X humans who are extremely mentally retarded, to the point that they have no long term goals, can probably only experience pain or joy in the moment, and are incapable of the more complex pleasures and suffering that a regular human would be able to. But those X humans must spend their lives locked in a box that is rarely cleaned, force-fed food that is unhealthy for them, for about a year or two until they are killed.
Then try the argument again, but replace the long description I gave with "human babies, who will never develop past baby-hood." Because I think it's legitimately similar. If there was a gene that caused a human to live up to about a year and then die, with no chance of growing up, but also be extremely tasty, would it be okay to clone a bunch of them to eat?
For the record, my answer in terms of "lives saved" for this question is probably around 10,000 (basically started with the life expectancy of the human, multiplied by about a hundred, which is about how much more I think the average human is capable of appreciating life than the average pig. Note that this is an average human. The numbers do change if I knew what kind of life the human was likely to lead). I could be persuaded that the coefficient should be a bit more, but I really can't imagine it being higher than x10,000, for a total ratio of 1,000,000 : 1. If you assign a higher number for the average human, I think that's a decision made purely out of human-centric bias rather than the value of intelligence or human capacity for joy.
And my answer in terms of "If you had to live your life being marginally less happy because you didn't get to eat tasty retarded-human-flesh, how many retarded-humans/babies would have to be saved in order to give up that amount of happiness", the number drops dramatically. Perhaps not zero, but not more than 10.
(Note: I wasn't quite sure whether this warranted a high level post or just a discussion. I haven't made a high level post yet, and wasn't entirely sure what the requirements are. For now I made it a discussion, but I'd like some feedback on that)
I've been somewhat surprised by the lack of many threads on Less Wrong dealing with vegetarianism, either for or against. Is there some near-universally accepted-but-unspoken philosophy here, or is it just not something people think of much? I was particularly taken aback by the Newtonmas invitation not even mentioning a vegetarian option. If a bunch of hyper-rationalists aren't even thinking about it, then either something is pretty wrong with my thinking or theirs.
I'm not going to go through all the arguments in detail here, but I'll list the basic ideas. If you've read "Diet for a Small Planet" or are otherwise aware of the specifics, and have counterarguments, feel free to object. If you haven't, I consider reading it (or something similar) a prerequisite for making a decision about whether you eat meat, just as reading the sequences is important to have meaningful discussion on this site.
The issues:
1. "It's cruel to animals." Factory farming is cruel on a massive scale, beyond what we find in nature. Even if animal suffering has only 1% the weight of a humans, there's enough multiplying going on that you can't just ignore it. I haven't precisely clarified my ethics in a way that avoids the Repugnant Conclusion (I've been vaguely describing myself as a "Preference Utilitarian" but I confess that I haven't fully explored the ramifications of it), but it seems to me that if you're not okay with breeding a subservient, less intelligent species of humans for slave labor and consumption, you shouldn't be okay with how we treat animals. I don't think intelligence gives humans any additional intrinsic value, and I don't think most humans use their intelligence to contribute to the universe on a scale meaningful enough to make a binary distinction between the instrumental value of the average human vs the average cow.
2. "It's bad for humans." The scale on which we eat meat is demonstrably unhealthy, wasteful and recent (arising in Western culture in the last hundred years). The way Westerners eat in general is unhealthy and meat is just a part of that, but it's a significant factor.
3. "It's bad for the environment (which is bad for both human and non-human animals)." Massive amounts of cows require massive amounts of grain, which require unsustainable agriculture which damages the soil. The cows themselves are a major pollution. (Edit: removed an attention grabbing fact that may or may not have been strictly true but I'm not currently prepared to defend)
Now, there are some legitimate counterarguments against strict vegetarianism. It's not necessary to be a pure vegetarian for health or environmental reasons. I do not object to free range farms that provide their animals with a decent life and painless death. I am fine with hunting. (In fact, until a super-AI somehow rewrites the rules of the ecosystem, hunting certain animals is necessary since humans have eliminated the natural predators). On top of all that, animal cruelty is only one of a million problems facing the world, factoring farming is only one of its causes, and dealing with it takes effort. You could be spending that effort dealing with one of the other 999,999 kinds of injustice that the world faces. And if that is your choice, after having given serious consideration to the issue, I understand.
I actually eat meat approximately once a month, for each of the above reasons. Western Society makes it difficult to live perfectly, and once-a-month turns out to be approximately how often I fail to live up to my ideals. My end goal for food consumption is to derive my meat, eggs and dairy products from ethical sources, after which I'll consider it "good enough" (i.e. diminishing returns of effort vs improving-the-world) and move on to another area of self improvement.