The irony here is that secular humanists (of which most atheists are), believe that humans are capable of a collective morality absent (faith-based) religion. It never occurs to them that the entirety of human history demonstrates that humans (individually and collectively) are more likely to act in an immoral manner in the absence of a moral code based on religion... put bluntly, their core belief is based on faith rather than on evidence.
>> It never occurs to them
It never occurs to them they don’t know what they’re denying.