You’re right, meat isn’t necessarily bad for your health (though, to be clear, there’s no data supporting the idea that McDonald’s meat is better or worse than other meat…except that it’s easier to eat a lot of it very quickly, and there’s a ton of salt…and you generally also consume it with fried potatoes and sugar water.)
But yes, there’s nothing wrong with meat in moderation…though diets high in animal protein have been found to be linked with cancer, heart disease, and premature death in humans.
But, on the whole, whether I live to be 73 or 78 is not so much of a concern to me as the overall impact I have on the world during those years. No one can deny that meat is horrible for the environment. Giving up meat would probably reduce your carbon footprint by more than giving up driving.
40% of grain produced in America is fed to livestock animals. That’s enough to feed 800 million people. 30% of the world’s total ice-free land is used to grow crops to fead to livestock. 30% OF THE WHOLE WORLD! Only 10% is used to grow human food crops.
There are ways to raise animals with less significant or even beneficial environmental impact…but we do not raise animals that way.
I’m not even touching on the cruelty, here. Let’s just worry about the Earth and not individuals for a moment…if we do that, meat is /clearly bad/ and we should all eat less (if we can), which I try very hard to do.