Ok, I'm going to try not to get too drawn in here, especially as wierd is showing some pretty strong signs that they'll not give an inch. I'll restrict myself to one post.
The argument (resource use), asserts that the land used (which it does not specify!) should be used for cropland.
Pretty sure you're talking at cross purposes here, or even not really reading what Radish wrote. I think Radish is talking about the land used to grow the stuff fed to non-grazed livestock. Not the feedlot, not the land used for grazing, but the place that grows the feed for the feedlot. At least 14% of which is edible to humans, some of it being corn. Presumably on land that could be used to grow corn for human consumption. Just a clarification.
I know you can graze cows, I've been in the country before. Never heard of someone grazing pigs.
In the UK, for example, apparently over 80% of pigs are raised in "intensive farms", and yeah, I got that from wikipedia, who apparently got it from the Agriculture and Horticulture Development Board.
https://en.wikipedia.org/wiki/Intensive_pig_farming#PopularityThese intensively farmed pigs are not resource efficient because they use feed. They are the most commonly consumed type of pigs, and possibly the only type some people can afford or even find. This is just one example: beef, and maybe mutton, are somewhat uncommon in not necessarily relying on crops.
So... yeah, there are resource efficient ways to produce
some meat. Not news. Are there enough resource efficient ways to raise enough for the 7.8 billion of us on the planet, minus Jains and Buddhists? Maybe we'll find out when we manage to outlaw beef feedlots, and I guess most pork, not all mutton, maybe lamb, I suspect chicken and many other birds, and a great deal of farmed fish. Until then... not consuming any of the inefficiently produced things is probably a good idea. As is learning to adopt a lifestyle that minimises or excludes such consumption, and prepares one for the possibility that the resource efficient meats will simply never be common enough to form a large part of one's diet. Focusing on beef alone is perhaps a little disingenuous, actually.
Feel free to ignore the argument for vegetarianism from resource inefficiency if it doesn't apply in your case - if a farmer shot a couple of squirrels and sold them to you, your squirrel and lentil stew would be as resource-efficient as it is delicious. I do think it's a fallacy to assume that any argument for vegetarianism has to cover all cases of eating any kind of animal under any circumstances. All you've shown is that there are multiple positions this argument might support - which makes it an argument, albeit not a decisive one, for all of them. Any argument for vegetarianism that shows that
in most cases the way we eat animals is wrong is a valid argument for vegetarianism. Ideologies like vegetarianism are always going to be supported by a
range of arguments, and can always become more nuanced.
One can always take any individual argument for a broad ethical stance and show that there exists some position outside it that the argument doesn't quite apply to. Doing so can result in a new paper for ethics professors, and a nice sense of superiority for amateurs, if nothing else.