There are some people that are vegan but also conflate that with non-GMO, or chakras, or some other fucked up shit. I'm vegan, so my only concern is "is this made from animals?"
If not, it goes in my belly.
The answer to your next question is "because I like burgers, but meat is made from factory-farmed tortured animals. The standards for slaughterhouses and human consumption are so low that you're actually eating literal shit, and probably pus from a cow's tumour. Yes, really. Plus, factory farming is the biggest environmental fuckup we've got going. (51% of the water in CA is given to animal agriculture.) You can eat a burger, yes, with cheese and bacon, and have it be vegan. Also beer, which is often, but not always, vegan."
The answer to your next statement is, "no, you don't. 99% of meat consumed is factory farmed. I'll tell you a story about my friend who told me that he only eats meat raised by his uncle, who is a hunter, and all their meat is organic, certified, farm-fresh. While he was telling me this story, he was pulling out a pack of store-bought, frozen chicken tosquitos and putting them in the toaster-oven.
"When you go out to dinner, when you stop at the drive-through, you get what they have. When you get milk at the coffee shop, it's factory milk."
I think that covers most of the follow-ups, but for the bingo card:
I live on an island already, and water is of greater survival concern than food.
No, I get all my vitamins and minerals from plants. Yes, I take vitamins, as do most people. Yes, they're vegan.
Protein is made by your DNA, not by consuming animals, and yes I lift.
That study has been debunked by new information. Try reading a news aggregate site or something.
No, I make exceptions for medicine, including vaccines*. It's about doing the least harm, not theoretical purity.
*not the flu vaccine, I'm "sensitive" to one of the antibiotics, and "sensitive" in the medical sense means I pass out for two days, waking only to vomit. The last time I took it I lost 8 pounds overnight.