@goodlife
People's brains are, supposedly*, "wired" to believe in something… anything, even. It doesn't seem to matter what it is, in detail but it gives them a detectable "buzz", which stimulates the pleasure centres in the brain. They "get off" on the endorphines released, in response to this stimulus.
I could have answered, cynically, that anyone would react vehemently, to an attempt to take their "security blanket" away but it is, evidently, worse than that, it is like having their favourite drug taken away, if their belief system is undermined, by something a heretic says, for instance.
For some reason, the powers of god(s) does not extend to killing heretics remotely and they generally require humans to assist them. Strange, that.
* The title of the research and its authors are not known to me at this time. I do not know if their research was motivated by, or influenced by, either atheism or religious fervour. It was featured in a BBC Horizon episode, some time in the last 25-30 years, minimum of 10 years ago).