You are imagining that the article said anything about gluten having anything to do with inflammation.
The article did not say anything about going vegan.
The Bolivian and the Malaysian tribes ate a whole food, plant based diet that was not exclusively plant based. They are on 2x the fibre of anyone in the West and they are not eating farmed animals that have been fed with commodity crops such as corn.
What this means is that their diet is incredibly low fat, and your summary does not point to that.
Regarding protein, animals get their protein from plants, and, if you eat enough plants, you will get enough protein unless it is processed. See Beri-beri and how that came about with American rice that lacked protein.
In the West, where we wash our food, we need a souce of vitamin B12, which can either be supplemented or come from meat. Plants have no need for vitamin B12 so they don't have any, even though they have everything else we need. If you don't wash your food then there is an abundance of B12 from bacteria in dirt, so it is not a problem.
Note that the tribes don't consume dairy, which is no surprise. Even the Romans thought it was a bit weird when they got to England to see grown men drinking milk from cows. In Rome the heat made that dangerous due to bacteria that get to the milk first, but the Celts had built a lifestyle around milk and they became lactose tolerant, to some degree.
Few claim to be lactose tolerant in adulthood, but how lactose tolerant are they? Really it is not a physiological tolerance, but a mental one, an acceptance that odd rashes and a digestive tract that works less than perfectly is normal, when it isn't. Milk is for babies, and it is species specific.
Anyone that tells you otherwise is just a victim of milk marketing and has not left milk out of their diet for long enough to realise that life without dairy is better.
Sugar is not the root of all evil, it just rots your teeth and feeds yeast-like bacteria all the way down your digestive tract. It is the combination of excess fat and sugar that is to be avoided if you want to avoid diabetes and all of the other non-communicable chronic diseases.
In summary, stay off the processed foods and stick to the government guidelines for nutrition.
This threw me off. I don't know anyone ethnically local to my area that is lactose intolerant except for one grandma and it indeed becomes more common with age. Nobody else has odd rashes or digestive tract issues linked to it. We know perfectly well how some populations have adjusted to being capable of properly digesting it so your claims seem wild. https://en.wikipedia.org/wiki/Lactase#Genetic_expression_and...