This totally validates my need to go play in the mud and eat sketchy food from carts on the street.
I'm not sure I buy the "hygiene is harmful" argument or that we've gone overboard with it. I think a lot of other factors that have changed in the past 60 years might factor in, including a misguided government/agribusiness lead food pyramid that is way out of balance with our pre-civilization diets, as well as the introduction of highly processed and sweetened food that for many of us forms the majority of our diets.
You can be hygienic and still cultivate behaviors that increase your exposure to safe levels of microbes. For instance, I always wash my hands after using the toilet but I’m less concerned than most about the use-by dates on food products and prefer to make decisions based on my sense of smell and taste. Not sure if that’s a good example.
Indeed, hygiene is not harmful, but we have gone overboard with it. As with most things in life, going to the extremes is bad for your health.