seeing as how veganism is not the default choice in most of the industrialized world, this is a misleading frame. it's also incorrect that it's more efficient to "eat animals" to produce muscle if we're being pedantic (as a
vegetarian, however, this is not a meaningless distinction to me)— amino acids in dairy & eggs have a measurably higher bioavailability than those in meat, whether ranked by the PDCAAS or DIAAS https://web.archive.org/web/20151010170125/http://www.idf-is....
That's a poor summary of the article you link, given that it says vegan diets are almost twice as efficient as the standard American diet. (It just also says that low-meat diets are even more efficient in terms of land use.)
Will you elaborate on the obvious reasons? Pretend they aren't obvious to me.
I'm interested in reading more about athletic advantages gained from consuming meat. Is there a reason that other sources of protein aren't giving the same benefit?