...which, if it turns into a cultural habit, will both protect against getting infected but also make future humans more susceptible to diseases since their imm

...which, if it turns into a cultural habit, will both protect against getting infected but also make future humans more susceptible to diseases since their immune systems have not had enough exposure. It might also lead to an increase in allergies, as can already be seen in the higher prevalence of such in modern clean suburban housing projects versus the countryside. A bored immune system will find other things to attack, including harmless agents or even the body it is part of.