That is because belief is something within a person. Of course if they believe that mumbo-jumbo they will think it is happening to them.
But when they take that personal, psychologically internal, experience and generalize it... especially when you give people advice such as "don't participate in a psychologically healthy practice because your mind might get trapped in the astral plane"... that's where we see the bad side of religion pop up.
Remember that religion is why apparently sane people:
Roll around on the floor of a draughty hall making stupid noises;
Blow themselves up;
Blow other people up;
Set themselves on fire;
Set other people on fire;
Go to war over a difference in interpretation of a 1000 year old book;
Try to stop the spread of new, verifiable knowlege;
Deny their loved ones life-saving medicine;
And so on.
So my advice: keep religion out of your meditation - except possibly to try to understand that religion is just an illusion created by your psyche and the expectations of your friends and family.