Oops, forgot about this thread :3
About that authoritynutrition.com article, I found someone who does a better job disproving it (it's funny too):https://www.youtube.com/watch?v=T1iodwaS0XQ
1) I'll need a link or something. A few anecdotes from some unnamed tribe is not enough to change my mind when all statistics and science indicate that some of the most serious diseases in the western world; heart disease, diabetes, osteoporosis and cancer, are all heavily correlated with intake of animal products.
2) Humans are very adaptable and we can survive on many things. Sure, we can survive on meat, but it's bad for our health in the long run. We have intestines similar to chimpanzees, who live mostly off fruit.
3) So you would be fine with someone killing your cat/dog/hamster/etc?
Killing isn't bad by definition, but 99% of all killings of animals are for bad reasons. If a grizzly bear comes charging at you and you happen to be holding a gun, no one's gonna blame you for shooting it. Sure, animals kill each other. They also rape each other and do other bad things, but that's no reason for us to do the same. Humans have a lot of the same primitive urges that you'll need to use self-control to suppress.. if you wanna stay out of prison.
4) The number of cows, chickens, pigs etc. would be drastically lower. Nature is good at controlling populations. Many of the disgusting and deadly diseases (salmonella, e.coli, BSE) that come from animal farms are an example of what happens when a species becomes extremely overpopulated. Nature has several mechanisms to make sure a species doesn't become too dominant. The only thing we have to worry about is human overpopulation, because we're very good at screwing nature over (at least in the short run). Hunting is also a more complex problem than you think, because it can lead to an increased population of the animal being hunted (e.g. deer).
5) Well, meat production is very bad for the environment. If we destroy the planet, we bring every animal (including humans) to extinction.
6) When slavery became illegal there were also a lot of slave owners who lost their jobs, but then they thought of something else to do.
7) Yes, medicine and better sanitation. I don't know why you makes it sound like it's "either us or them". Again, the survival of all the Earth's species (including humans) very likely depends on us being able to change our way of life, since right now the animal agriculture industry is responsible for more than 50% of greenhouse gas volume.
You've got it wrong. There is less food in the world because we funnel it through animals instead of eating the source. For example, the rainforest is being chopped down to make more fields for soy beans. 90% of these soy beans are used in feed for farm animals, and we lose 80% of the nutritional value of the original soy bean this way.
9) That's a silly straw man
but if I found a spider in my room I'd take it outside. Unless it was a giant spider with big poison fangs or something, then I'd probably kill it to avoid getting bitten.