> The idea that we should have moral compunctions about biological reality seems absurd to me Why? We seem to have plenty of moral compunctions about lots of other biological realities. Otherwise, why do anything at all? As humans, we have so far not acted in a manner that implies we're completely OK with biological realities. We keep trying to change them. Hopefully, it will continue this way. Most people agree that…
Do we, in practice? Can you go into more detail?
> Most people agree that they do not want to suffer. That's what makes it evil. It's not a difficult concept.
Did we ask the animals too? Maybe the pig consensus is different.
If most people agree they do not want to pay taxes, do taxes become evil?
There is no objective reason to consider 'most people agree on x' as some kind of objective moral imperative. There is no moral quality to caring what people want. I don't think this is a very sound basis for an objective morality.
EDIT: What I'm trying to get at is basically this. You're saying that eating meat (at least meat that necessitates the killing of animals) is morally wrong. You're saying this because you want to persuade me and the rest of your audience that eating meat is morally wrong. But you are not a moral authority; I consult my conscience, which feels entirely guilt-free about the subject, and my appetite, which feels a positive obligation to eat meat. You're simply trying to exploit a "hack" in my social animal brain, which is that if you tell me that something is wrong, you are telling me that other members of the human herd will judge me unfavorably and perhaps ostracize me or otherwise punish me.
Some people, but not very many, will be swayed by your attempted brain-exploit. But I, again, observe that my conscious feels guilt-free, which is a very strong sign that the people I am surrounded by do not, in fact, disapprove of my eating meat, and also that the vast majority of people I know actually eat meat. So somewhere in my hindbrain, I realize that you are (from my perspective) lying to me, and it will make me instinctively resentful of you, because you have marked yourself as a member of The Other.
So your 'moral' argument is, objectively, amoral; and for your purposes, actually counterproductive, useful only when a person is surrounded overwhelmingly by vegans and vegetarians, who will be able to enforce a shared social norm. You could, instead, if you want to try an intellectual tack, try to show how my personal interests are served by becoming a vegetarian, but you will have to discover some interests and values that strongly outweigh my predilection for eating meat.
Or what you could do is abandon your moral arguments, temporarily, until a day when you're worried about punishing the wayward vegans rather than converting the meat-eaters. You want to make vegans cool, the social elite. You want to get into the media and fill as many TV shows and movies and podcasts and YouTube personalities with cool vegans. You want to make people want to be like you. While you're at it, make animals more important, anthropomorphize them as much as possible, try to generate as much empathy for animals as possible - to some degree, this is already being done. And then in a few decades, if you keep it up, most people will be vegetarians and you can then start talking about how killing animals for food is evil, and you can probably even pass a law to that effect. That'd be a way to get some moral feeling behind it.