It's more of "getting the immune system to respond appropriately" and it's difficult to achieve that balance. The immune system isn't a one-size fits all monolithic entity. For example, inflammation in appropriate levels is beneficial for you because it allows your body to heal; long term sustained inflammation is not.

Too often there is this black-white level of thinking (not pointed at you) in health that causes people to act against their self-interest.

edit: the fact that this type of paper is coming from an ecologically-focused study, rather than a medical journal-based study gives me pause, too.