Well, Kale Brock visits three out of six blue zones and has a good time. Not sure why he misses the opportunity to visit all of them.
There is no scientific approach to get to the bottom of longevity. Instead of taking with scientist who are researching this issue like Valter Longo a Professor for Gerontology with some awesome breakthrough research, Kale Brock is talking with some nice family doctors and general practitioners. None of them are well known for anything in the research field of longevity.
A substantiated comparison of all six blue zones is missing completely. It's all anecdotic reference.
Statistics would be nice to have. For example, which percentage of people in these blue zones are smokers/non-smokers. Contemplating typical risk factors with any kind of survey, is not something Kale Brock is looking for.
New research about risk factors like PUFAs (Polyunsaturated fatty acids = typically seed oils), in the context of blue zones is missing completely.
If your reasoning about a complex issue does not need any kind of scientific background, this may be a feel-good documentary you could enjoy.