Zola didn’t expose anything. He ignored hard evidence because it didn’t fit his worldview. And Zola and most modern “skeptics” are not classical skeptics, but naturalists. They assume that everything has a natural explanation if only we can find it. It is their version of “god of the gaps.”This causes a problem when they look at the nature of man, because basically we see what we see in the mirror.
I freely admit to not being familiar with M. Zola and his experience at Lourdes. Was the alleged "miracle" that he was presented with was documented to the point that fraud could be eliminated?
In any case, when supernatural claims are investigated today with sufficient rigor to eliminate cheating, they evaporate like a puddle of water on a hot day. It's notable that out of the hundreds of people who've tried to demonstrate magical & psychic powers in hopes of claiming Randi's million dollar prize, not one has succeeded in demonstrating any paranormal abilities.
Might there be something to all this supernatural wackiness? I suppose so...maybe out there someone really can levitate, read minds, or magically heal through faith. Maybe there really are aliens in UFOs, Bigfoot, angels, and the Loch Ness Monster. But extraordinary claims require extraordinary evidence. Until someone can actually produce verifiable evidence that holds up under scientific scrutiny, it's perfectly reasonable to have the default position that these sorts of things are so much bunk.