Thank you for your extensive reply. I will make sure to address all of your points.
(1) Humans do not need animal products to be healthy.
Citation needed. When providing citations, please note that (a) much of nutrition science is very shoddy (in all the usual ways—methodology, replicability, file-drawer effects, etc.), and (b) there is considerable variation, between people and between groups of people, in optimal diet, physiological responses to dietary changes, etc. Almost any universal statement about human nutrition is likely to be wrong. So a claim like this requires considerable support to be raised even to the “plausible” level, much less to “certain enough to base moral claims on”. (Indeed, it is possible that nutrition science, in its current state, is simply not capable of providing us with the degree of certainty which we would need in order to use a claim like this in a moral argument.)
Citation for the claim:
The source is from the Academy of Nutrition and Dietetics. In regard to the institution you stated the following:
Under no circumstances would I believe a word these people say about nutrition.
You quoted their Wikipedia page and that they profit from funding. However, according to that same Wikipedia article, they are still the largest organization of food and nutritional professionals. Every large institution needs money. They do science. Your own opinion in not trusting their science does not make their science any less credible IMO. However, here is a further source that links to several other organizations that have affirmed that vegan diets are healthy:
https://www.veganism.com/is-vegan-diet-healthy/
I hope that addresses argument (1) sufficiently.
Indeed, it is possible that nutrition science, in its current state, is simply not capable of providing us with the degree of certainty which we would need in order to use a claim like this in a moral argument
I think you should not underestimate nutritional science and do your research first if you make such a claim. The scientific findings are sufficient to claim that vegan diets are healthy. Therefore, humans do not need animal products to be healthy.
(2) Therefore, the consumption of animal products is unnecessary.
Granting claim (1), this one does not follow. You seem to imply that something is only “necessary” if, without it, we would die (or suffer serious harms to health). I reject this view.
I would like to modify my original statement: The consumption of animal products is not necessary in order to be healthy. Therefore, they are unnecessary for human health. This makes their consumption optional, a choice. If you can choose non-violence over violence, I think that is a moral imperative (to which I was referring in my title).
(3) This makes the killing of non-human animals for animal products unnecessary.
Note that if your argument depends on establishing the immorality of killing animals, that gets you to vegetarianism only, not to veganism. Eggs, dairy, etc. do not require killing animals, so a non-vegan vegetarian might well ask—how does this argument apply to me?
Again, a slight modification to clarify: The killing of non-human animals for their products is not necessary for human health. Concerning your points about eggs and dairy: Yes, they very much require killing.
(a) The egg industry kills male chicks on the first day of their life, usually by throwing them in a big blender. On another note, chickens that produce eggs suffer from horrible conditions in the majority of cases, which again is suffering not necessary for human health.
(b) The dairy industry does not need the male calves, which are being killed either after a few days or after a few weeks (for veal). Most dairy cows also get slaughtered after 4 to 5 years because their production of milk decreases. Again, there is also a lot of suffering in the industry besides the premature killing of sentient beings, which can be avoided by being vegan.
(Kindly note that the arguments used in (a) and (b) are derived from the book Why we love dogs, eat pigs, and wear cows by Dr. Melanie Joy.)
(4) Not avoiding unnecessary suffering is immoral.
The word “unnecessary” seems to be doing most of the work in this claim, but it’s difficult to see how to operationalize it. Interestingly, utilitarianism (which is usually a background assumption in arguments like this, and likely here as well, though you never name it explicitly) doesn’t much help; there isn’t really any way, for a utilitarian, to designate some suffering to be “necessary” or “not necessary”—it simply gets entered as input into the utility calculation, along with all other relevant facts about the world. On the other hand, most non-utilitarian views don’t offer any clear way to make sense of this claim either.
I do not know if this holds up against your argumentation, but I would like to try anyways: I define unnecessary suffering in this case as suffering that is not essential to our lives. If the only reason we consume animal products is pleasure, the question is the following: Can we justify the suffering of others only because it gives us pleasure? As I see it not avoiding the pain and suffering of millions of animals just because we like their taste is immoral.
(5) Therefore, contributing to unnecessary animal suffering makes you an animal abuser.
This presupposes several other claims, which are missing from your argument, and must be made explicit. These include “non-human animals are capable of suffering” (and/or “the suffering of non-human animals is morally relevant”).
As a side note, the term “abuser” is tendentious; clearly, you are trying to bring in the connotations of the term we use to describe people who beat their pet dogs, into the argument about whether it’s acceptable to kill cows for their meat. If you have a point, make it without recourse to underhanded emotional tactics.
Non-human animals are capable of suffering and their suffering is morally relevant. If we cannot agree on this point, I see no point in discussing the other matters further. That they are capable of suffering is not only obvious to anyone who ever witnessed some non-human animal suffer, but also scientifically proven. They have brains, feel physical and emotional pain. Not considering their suffering morally relevant is, analogous to sexism or racism, speciesism. Only because they are not part of our human “in-group” does not make them irrelevant. Please google the term yourself if my explanation was not sufficient.
Concerning the term animal abuser: There are no underhanded emotional tactics. I made the point so people make the uncomfortable connection in their heads for themselves. If you pay for animal products, you pay the industry that causes them suffering and pain. Therefore, you are causing suffering and pain to animals. That is the definition of an animal abuser in my book.
(Please also see my response to your other comment.)
Due to time constraints I only want to briefly respond to this point. Do you not agree that they can suffer or do you not agree that their suffering is morally relevant? Either is quit shocking to me actually. There is nothing morally wrong with someone kicking a dog around for fun? If you have time and are interested maybe you care to watch a few minutes of this documentary, maybe it can awaken your compassion!
Otherwise, good chat everyone. I grew tired of this quickly! In all fairness, I am lazy and you are way better at arguing! Anyways, I hope you have a good life and I will make sure to delete this account in some time.