I don't usually disagree with Scott to this degree.
Uh, that's not how ethics works. Unless you're a strict Utilitarian. Which I'm not, and find absurd. Save the Children claims to save a child's life for $1/day. By his logic, if we assume the average child is 10, a serial killer should be pardoned so long as he donates $3650/human killed.you’re currently killing 0.6 animals per year. If you donate six cents per year to animal-related charities, you’re animal-neutral.
If killing animals is considered wrong, and you can live without eating meat, then you should do so, not bullshit around picking the "biggest' animal that causes the least deaths per calorie. If everyone "offset by donating to charity" then the charities would cease to be effective, because nobody would be able to say "I should stop" because of some false idea of being able to do "anti-harm" and letting it make up for harm. Guess what is a better outcome than donating to charity when eating meat? Not eating meat and donating. You want to be moral and take some bullshit-empathetical-view of reality where animals are precious life that shouldn't ever be made to suffer, then you can not eat meat, don't beat around the bush. I eat meat because I don't think it's wrong to kill a chicken, even if they have "full emotional lives". If I did think it was wrong, I would stop. Just like if I believed in the bible I would donate everything I owned to the poor, and live a life preaching the gospel, as you are supposed to. If you can't live the life you signed up for, don't sign up for it.
To be fair there are also land and resource use/animal welfare motivated vegetarians and vegans that aren't necessarily concerned with the killing itself but they seem to have little understanding if grazing, crop rotation and cover crops, otherwise they'd be forced to take a more nuanced position.