Renji,
I think one of the dynamics at work here is that the integrity of your former belief is not inviolable, and this is a threat to the faith of your friends. That you, someone I assume they respect, could find fault with their beliefs means that doubt is an actual possibility, and they can't admit room for such a prospect. For some, holding on dearly to the comfort of religious belief is a number one priority, and to think such comfort could be abandoned for the logic of disbelief is too much to handle. They would prefer to ignore you than to have you around as a friend who reminds them of the vulnerability of their belief. So, it isn't you who they are pushing themselves away from, but the reminder you represent a possible fracture in their faith. It's sort of an "I can't hear you!" they're resorting to---out of sight out of mind. From my experience, few people of this sort seldom enter into a debate about the veracity of their faith, it's far too unsettling.