I think Laudan's major point (because I know she's a lover of the traditional as well) is that there's a conceit in those who insist on a very strict definition of authenticity that exists more in their ideal of a cuisine than in the reality of that cuisine. It's not an ethical or aesthetic point. She's not saying what *should* be, but just describing what is.
Personally, I think it's imprecise and faulty to insist on authenticity as originality, ie, the genesis of a dish or cuisine. There's no way to nail that down. What is the original taco? Is it the taco pre-conquest? Is a taco al pastor an authentic taco? There were no pigs prior to the conquest. Is flan or churros authentic Mexican desserts? They were Spanish first. Is a burrito or flour tortilla an authentic Mexican dish? Most foodies seem to think not despite the fact that Mexicans in Sonora invented them. Are nachos and fajitas Mexican? Again, most foodies seem to think not, despite that Mexicans in Texas invented them. Etc.
Honestly, I think that a search for authenticity is a fool's pursuit. The best you can do is act like a historian asking: "What were the best or most interesting dishes or versions of dishes at a certain time and a certain place?" And the question of authenticity probably has to be reduced to just a question of what people eat at a certain time and place. Is Bimbo bread authentic Mexican? Sure, Mexicans created it, eat it, and even like it. Is a McDonald's burger authentic American? Yes, and for all the same reasons.
Of course, what's authentic has nothing to do with questions of quality.
What we should do, imo, is get away from the question of authenticity and that's part of how Lauden's article has informed me. We should be concerned instead, I think, with maintaining traditions and technologies before they're lost.
I don't mourn the movement in Mexico away from tortillas and towards bread because it's a loss of authenticity. I mourn it because the knowledge of how to make a lovely food like tortillas is moving out of the skillset of Mexicans. In the same way, I mourn the loss of garum, even though it's no longer a part of authentic Meditteranean cooking.
The problem, of course, is that as one horizon because visible in our future, one almost necessarily falls away in our past and something as "living" as a cuisine can't be forced into stasis anymore than we can keep the sun from going down. And I don't know that I'd want that to happen anyway. Imagine how much would have been lost from our future if native Mexicans hadn't adopted or adapted to Spanish influences.
In the same way, I think it's a bit foolish how Europeans, especially in France and Italy, try to straight-jacket what is this food and what is that dish. It's a corny attempt to freeze time and put a static label on something that developed often over hundreds of years and will probably go on developing even if it can't be legally called Neopolitan pizza or whatever.
Good historical and archeological work, chronicling of technologies and recipes, is great and worthy work and allows for something that might be lost to be found again.
Despite all that, I think that anyone who truly loves food and truly is interested in a cuisine should make an effort to understand and search out its traditions. Just like I imagine Pablo Picasso had an intimate understanding of the skills and works of the masters that preceded him before he started creating new traditions, a cook or diner should do the same. I think they'll benefit from it.