I wonder how you can justify eating meat, without knowing the arguments against eating meat. To my mind there are practical arguments, ethical arguments, and emotional arguments for not eating meant.
Practical arguments include things like: cow farts are contributing to global warming; or cow farming is causing great regions of the rain forest to be destroyed, wreaking havoc with the water cycle; or that cow farming is destroying the biodiversity contained in the rain forest; or growing meat uses up too many resources and if we were all vegetarians, we could feed everyone in the world.
Ethical arguments include things like: animals are brought up in cruel conditions and that’s just wrong (presumably because animals are sentient to some degree, and thus like us); or animals suffer a great deal when we grow them and kill them for meat; or we have to kill them, and killing is wrong; or, if you couldn’t kill the animal personally, they you shouldn’t be eating meat.
Emotional arguments include: how can you kill a cute, cuddly (fill in your animal here); my dog is a person, so all animals must be people; and there are probably others that I can’t think of now.
A note about ways to counter these points
For the ethical people who don’t want to kill, I always wonder what they think about killing the millions of animals that will have to be sacrificed in order to go back to a vegetarian way of life. Food animals have evolved to be valuable to the most powerful animal on the planet, and thus encourage us to expand their numbers. If we all went vegetarian, no one would have any incentive to take care of the animals. They go free, and wander around, getting killed by cars, or they’d starve. Is this what is wanted?
As to the idea that animals suffer when calves grow up in cages, and other animals have horrendous conditions, I think the marketplace will take care of that. That meat doesn’t taste as good, and eventually no one will want it.
As to emotional arguments, there’s nothing I can do. Emotion is not subject to reason very much. If you think animals are like people, like people in a coma, or like people with nonstandard mental abilities, there’s little to say about that. I don’t agree.
Practical arguments are more difficult. I think you can counter the food argument, since it is clear that starvation is a distribution problem, not a type of farming problem. The rain forest arguments are troubling. It’s hard to predict what would happen if the rain forests weren’t being cut down to grow cattle. Would they be cut down for other reasons?
The biodiversity argument makes a lot of assumptions. Is biodiversity as good as we think it is? Are we losing biodiversity with the rain forest? Are new animals and plants evolving at a pace similar to that of extinction of species? We don’t know, for sure, any answers to these questions.
Anyway, I think that if you outline the arguments for vegetarianism, you have a better chance of seeing the other side of that issue. I hope I have provided a start to that approach here.