I would rather say we should make it illegal to do things that cause an inordinate amount of suffering to animals. I would prefer not to kill the dog either, but since most people in this thread seem to believe a vegan diet with supplements is impossible for carnivore pets, what other option is there?

I don't think it's impossible but I do think it leads to the suffering of pets because most animal owners aren't capable of taking care of their pets right now and they'll be even less capable when they need to follow a relatively strict diet for their pet.

However If I had someone who would pay someone else to torture 1 animal a day, and then eat it, meaning ~30,000 animals would be tortured throughout their life, and I have no way to make them stop besides killing them, what is your proposed solution? I want to hear the non utilitarian answer to this problem, in this hypothetical where killing them is the only way to stop the behavior.

About that specific person? You do nothing. You can't force people (or animals) to live a different life. What you want to do is get a societal shift. Educate people so they'd willingly switch and over time (if it's reasonable and I do think going more vegan is reasonable) society will shift away from eating animals and those people will disappear with time.

You’ve baked in that the only options are “kill people who eat meat” or “do nothing.” In a situation where all humans were strict carnivores, that’s a much harder question.

If would argue if humans were strictly carnivorous the question would be much easier, because then eating meat is our nature and we would die if we went vegan. The reason we (and dogs) can go vegan is because from a dietary perspective we're both omnivores. For example with cats there's no question, they're biologically not adapted to plant based diet. Their entire diet would essentially be supplements and they get next to nothing from eating plants.

Obviously I would hope to have legal or social consequences for people who eat meat.

The most “moral” thing to do would be for vegans to make it impossible for factory farming to exist,

I guess if you don’t value animals at all, you would never kill the person.

And these are the examples why I have a problem with Veganism and why I think Vegans like you are a detriment towards people going more plant based with their diet. Because you're all about moral superiority, absolutes, guilting others for their lifestyles and assuming the worst. You won't change peoples mind if you call them a piece of shit. You also won't change their minds by not compromising on anything. And this "all change must happen instantly because we demand it" message is just childish behavior.

If you're serious about getting people to eat less or no meat you can't expect instant results. You need to let people change their minds instead of trying to force them to change (and that includes trying to guilt them into changing). Also you can't change everyones mind but you need to change enough to for society to change over time. It's a process and it needs to be treated like a process. Don't force people, educate when you can and hope people change. After-all (hopefully) nobody forced you into becoming a vegan.