Am I missing it, or is there no mention of genetics in there? That seems like such a massive oversight that failing to address it makes this meaningless.

It’s like comparing the space/time complexity of different programs without looking at the code - and instead only looking at the language it was written in.

I have had this same thought every time anyone brings up these longevity studies. For the most part the blue zones are isolated locations that would likely have genetically distinct populations. It may be that these groups are genetically predisposed to exceptional longevity or that they're simply especially well adapted to the traditional diet of their location. Either way the findings wouldn't generalize to any useful dietary guidelines unless you're descended from one of those populations. The one exception might be Loma Linda, not very isolated but home to a large population of Seventh Day Adventists who are vegetarian, but I'd be willing to bet that it's still more genetically homogeneous than your average US city.