Meta: you've framed this as if Elizabeth had failed to respond to your linked comment while writing this post, so I would like to point out for others that the linked comment was written two days ago, in response to Elizabeth noting in the comments of the current post that you had not replied to her questions months prior.
These are cached arguments that are irrelevant to this particular post and/or properly disclaimed within the post.
The asks from this post aren't already in the water supply of this community; everyone reading EA Forum has, by contrast, already encountered the recommendation to take animal welfare more seriously.
I think the distinctions Richard highlights are essential for us to make in our public advocacy—in particular, polls show that there's already a significant chunk of voters who seem persuadable by AI notkilleveryoneism, so it's a good time to argue for that directly. I don't think there's anything gained by hiding under the banner of fearing moderate harms from abuse of today's models, and there's much to be lost if we get policy responses that protect us from those but not from the actual x-risk.
If someone uses the phrase "saving the world" on any level approaching consistent, run. Legitimate people who are working on legitimate problems do not rely on this drama. The more exciting the narrative and the more prominent a role the leader plays in it, the more skeptical you should be.
- (Ah, you might say, but facts can't be too good to be true: they are simply true or false. My answer to that would be the optimizer's curse.)
I don't think the problem stems from how important an organization thinks their work is. Emerson's meme company had no pretense to be world-saving, and yet had toxic dynamics as well.
The problem is that high stakes are not a reason to suspend ethical injunctions or personal boundaries; those provide more protective value when applied to something with genuinely high stakes.
You saw the counterarguments section "The human health gains are small relative to the harms of animals", but presumably missed that the next section was titled "The health costs don't matter, no benefit justifies the horror of farming animals", and made that exact counterargument rather than responding to Elizabeth's preemptive response.
I downvoted you because you responded to a very legible and effortful post (after going to a lot of trouble testing EAs and finding them nutritionally deficient to the point where it might affect their work), a post making the author's cruxes clear, and what kind of evidence would change her mind, with incredulity, accusations of bad faith, and a brazenly made-up number. I don't find any of your later arguments to be of sufficient quality to reverse that judgment.
The obvious case where someone might be hard pressed to be healthy on a vegan diet is when someone has allergies to multiple things that are ingredients in many of the common vegan protein staples. This is common enough that I've met ex-vegans who had to compromise on their diet for this reason, as well as a vegan who seemed very clearly nutritionally deprived because of FODMAP and gluten allergies but was toughing it out regardless for ethical reasons, so I'd be quite surprised if you've never met someone with multiple allergies that severely constrict their vegan options for getting the full spectrum of known nutrition. (Supplementation can help but is often less effective than nutrients in their original context.)
"Some cultures don't eat meat" does not in fact prove that nobody has nutritional deficiencies from not eating meat; some people in those cultures may be nutritionally deficient for that reason! That's like saying that because bread was ubiquitous in Europe, no Europeans have issues with gluten.