This is actually a well written no-hyperbole representation of interesting original research, makes no generalization. So your criticism might be misplaced. Th

This is actually a well written no-hyperbole representation of interesting original research, makes no generalization. So your criticism might be misplaced. The alternative hypothesis you discuss is not necessarily mutually exclusive with the findings in this research though. It all depends on what microbes you define as harmful, though at that point why even bother with the original generalization anyway?