Basically it means that there is a difference in a key personality trait that is linked to spirituality/religion when certain areas of the brain are damaged.
It means that these researchers are dopes. I could walk down the street with a Glock and pump a round into the chest of a couple dozen people, and I can pretty much guarantee you that all of them will have a heightened state of transcendental self-referential awareness. If need be I can repeat the experiment as many times as you like, with similar results. I have therefore just demonstrated a causal relationship.