I do the same, until there seems no possibility it would come from natural means. Even clergy do the same, in the case of possessions, for example. The person supposedly afflicted has to first undergo many psychological tests and medical tests to rule out mental disorders and such. Then, if their “symptoms” match up with what is commonly seen in possessions, and their medical and psychological tests come back fine, they can go forth with the exorcism. Many are then cured from their afflictions after having the exorcisms performed.
Supernatural origin is as much a theory as is evolution because neither can be completely, factually proven. Evidence can be gathered and people come to conclusions based on what is most likely.
With the Eucharistic Miracle I described, that is what happened. We are given the facts and we come to a conclusion. Some may disagree with it, but it is all based on likeliness. To deny the possibility of the supernatural in response to an event, is to deny a possible explanation or theory for something previously thought unexplainable.