Mayonnaise is safe because the acidity is sufficiently high that the pathogenic bacteria we're worried about can't grow. A 100 day experiment isn't very long. The figures I've heard for salmonella % in chicken is on the order of 0.1% Good chance he never even encountered it. Also depending on where you are, producers are required to vaccinate their chickens against salmonella. That makes raw chicken even safer to eat. Similar measures in North America for pigs have made undercooked, and even raw, pork pretty safe to eat; it didn't used to be.
This stuff varies per person anyway. We do after all have immune systems, and in most people they work pretty well. Especially if you've had prior exposures to pathogens you're encountering again, and have recovered. Sickness varies per person too. I've done strenuous long distance hikes with, sufficie to say, "stomach trouble" and survived just fine. Other people who are in even worse shape than me wouldn't have done so well. I also have a pretty high tolerance for things sucking before I really complain, at least while hiking. 😂
I don't think the tradition of never eating raw chicken has to do with salmonella at all, it's just terrible for your digestion. And mayonnaise was only an example, I've eaten raw eggs with sugar for breakfast for years, it's delicious.
No, it's because of salmonella. In chickens infected with salmonella, unlike other animals, the salmonella is present in the flesh itself. And it's pretty common for chickens to be infected.
May well be it. I personally hate the consistency of raw chicken. Maybe instinctively we evolved to hate it because of salmonella. Raw fish? No problem, raw beef? Yummy. But I cannot swallow raw chicken and I generally ask my money back wherever they serve me that thing (it's happened a couple of times!)