It is just one data point though. We know that better hygiene has saved millions of lives. The problem is when people think being clean is good, then taking 5 showers a day is even better. One can overdo it and end up worse.

There is also a big difference in what we need to protect against and what is less important. Being out in nature far away from people is in many way safer. In dense urban areas disease spreads more easily and hygiene becomes far more important. If being dirty was good, then they wouldn't have died like flies in historical dense cities like London.

Primary concern is cleanliness around things like food. Getting dirty from just reagular dirt on the ground out in the woods isn't dangerous.