Because the fact is that religious experiences are commonplace in this world.
They are not, that is not a fact, what you mean to say is:
According to peoples perception they believe they experienced a religious experience and these religious experiences perceptions are commonplace in this world.
Billions believe in a god with no evidence, you are always then going to have people say they have communicated with god, many people saying this does not constitute evidence god is communicating with anyone.
As I say it is all to do with circumstantial evidence and beyond reasonable doubt because there is no concrete evidence either way.
The circumstantial evidence points to no god if you are neutral and free from cognitive dissonance.