(1) Re: "How can we, with any authority state for certain precisely how the texts read?"
In the specific instance mentioned (with the link to the article provided) we know precisely what the ancient text does not
say. In this case, modern "interpreters" have added a whole phrase (with a concept not stated in the text), so we are not debating the significance of the canon in the abstract, but looking at a case of modern people intentionally mis-representing (if not re-writing) what the text plainly does say.
(2.1) Those are flattering words from Anagarika: sadly, however, my career in Pali has been over for several years now, and I will never again attempt the type of heavy lifting you describe.
You can read an interview about the final chapter of that career, here: https://medium.com/p/9df3f5f826e4
I no longer have any possibility of returning to work on Pali (nor any other form of Buddhist text).
(2.2) I agree, that this is the general situation: a majority of people depend on a small number who do (as Anagarika says) the heavy lifting. This is another reason why fraud and intellectual dishonesty (amongst that small number of people) can be so harmful (in the 21st century); the relationship is indeed one of dependency. Even amongst scholars, a relatively large number of researchers need to turn to a tiny number of Pali scholars to answer questions about what the texts do (and do not) say.
On this issue (vegetarianism) good luck getting an honest answer out of anyone (layman or monk); instead, we have a thousand years of people saying, "Don't worry, my butcher is muslim", and (the laziest excuse at all!), "There's no bad karma if you don't think about it, because karma only arises from mindful intention" --a doctrine that does, in fact, endorse mindless killing (!) as superior to mindfulness of the consequences of what you're doing, buying etc.
(3) I do not sympathize with the tendency to offer contrived cynicism about the possibility of knowing anything from the study of ancient texts. If you're looking for a religion based on pious ignorance, Theravada Buddhism is the wrong choice
. I find that people only offer this cynical disclaimer when it suits them (e.g., in this case, as an excuse for eating meat, "Well, how can we really know what the ancient texts were supposed to say?") and then allow themselves to uncritically adopt other material without any skepticism.
The generalized lament of, "How can we know anything about ancient authors at all?"
is certainly a strange contrast to the active, engaged attitude of scholars in establishing (e.g.) what we can (and cannot) know about an ancient author like Plato. I have a separate youtube video addressing this: we can
know a great deal about the ancient philosophy of the Buddha, in exactly
the same way that we know as much as we do about the philosophy of Aristotle --and it is, indeed, hard work (and heavy lifting).http://youtu.be/GzOcSpxKVoA
I think it is very sad when people pretend that any of this is "unknowable"; I think that is simply an abdication of responsibility for one's own ignorance (and, BTW, the Buddha has a lot
to say against ignorance).
Returning to this specific example (vegetarianism): as I argued in that article, the reality is that most people don't know what the canon says about it, precisely because there is so much dishonesty and discomfort for Buddhists themselves in confronting what those ancient texts say --and what the ancient philosophy really is (and isn't). I say that with some degree of sympathy for the people involved: for most people, it is very difficult to accept that their own grandparents were wrong, and that the opinions about Buddhism passed down in their own family may be deeply flawed (even if it is relative to the writ of the Pali canon).