Air Water Ground: Deus Vult

“If thy brother, the son of thy mother, or thy son, or thy daughter, or the wife of thy bosom, or thy friend, which is as thine own soul, entice thee secretly, saying, Let us go and serve other gods, which thou hast not known, thou, nor thy fathers; Namely, of the gods of the people which are round about you … Thou shalt not consent unto him, nor hearken unto him; neither shall thine eye pity him, neither shalt thou spare, neither shalt thou conceal him: But thou shalt surely kill him; thine hand shall be first upon him to put him to death, and afterwards the hand of all the people. And thou shalt stone him with stones, that he die.”

Deuteronomy 13:6-10

https://creationsciencestudy.wordpress.com/2013/11/27/should-we-stone-atheists/

"Without pledging ourselves to any particular Confession, we have restored faith to its pre-requisites because we were convinced that the people needs [sic] and requires [sic] this faith. We have therefore undertaken the fight against the atheistic movement, and that not merely with a few theoretical declarations: we have stamped it out."
Baynes, Norman Hepburn (1969). The Speeches of Adolf Hitler, April 1922 – August 1939'. H. Fertig. p. 378.

"Another ramification of our social nature and intelligence is pseudospeciation. Quoting from Jane Goodall's "Chimpanzees of The Gombe"@ 532: "In our species cultural evolution permits pseudospeciation (Erickson, 1966)--the transmission of individually acquired behavior from generation to generation within a particular group, leading to the customs and traditions of that group. This process is analogous to the formation of species through genetic inheritance. Pseudospeciation in humans means, among other things, that members of one group may not only see themselves as different from members of another, but also behave in different ways to group and non-group individuals. In its extreme form pseudospeciation leads to "dehumanizing" of other groups, so that they may be regarded almost as members of a different species (LeVine and Campbell, 1971). This process, along with the ability to use weapons for hurting or killing at a distance, frees group members from the inhibitions and social sanctions that operate within a group and enable acts that would not be tolerated within the group to be directed toward "those others”." The expression of pseudospeciation in such behaviors as ethnocentrism, racism, prejudice and warfare compound the scarcity condition or perceived scarcity, and increase the perceived threat levels for individuals seeking to meet needs. What results is an interaction between status related behaviors and pseudospeciation which often leads to inter-group violence and increases cultural isolation. As humans became more technologically sophisticated, this situation becomes increasingly acute due to inherent feedback loops. Resources disappear at an increasing rate, wastes accumulate at an increasing rate and violence increases in lethality and in incidence. Scarcity increases. Perceived threats increase. It all feeds back onto itself."

In my country, polls routinely inform us that when it comes to elect- ability, an atheist is at the bottom. Another poll found that the majority of Americans thought an atheist was less trustworthy than a rapist. Even on the so called "left" it is little different. The PC police overlook anti-atheist language and images.
This attitude toward the atheist minority is so wide spread here that it makes a good subject for looking at the underpinnings of the problems that can arise from contingent altruism.
Contingent altruism is cooperation by phenotype with conspecifics that display shared labels, markings or other ques; sometimes referred to as “tags”. It is found in social species. The reaction to tag, or its absence is a continuum of behavior. The more intelligent the specie the more graduated the responses.
Presence of a tag: trust or greater tendency to trust.
No tag: react by attack or a lesser tendency to trust.
In its most basic form, it can just be predicated on the presence of a chemical compound, such as the "nest scent" of ants.
Present: exchange pheromone information or food.
Not present: release alarm pheromone and kill or run.

In social birds and mammals, it gets more complex. With us, the most complex social creatures we know of, it can get byzantine. We learn to see a multitude of tags and responses thereto from our parents, siblings, peers, and eventually, from our own experiences.
Some basic apparent differences (skin color, gender, language/dialect, dress) seem to impact on how much we trust, depending what we have learned as a young creature. Other tags (team logos, and other minutinae for example) seldom have body counts.
To "discriminate" (pseudospeciation) is a cultural universal, but what we discriminate against is learned. The belief in a supernatural, unseen being is another cultural or "human universal". Which type of religion or spiritual practice one has, if any, is usually that learned from the parent. and it can have teeth and a body count.

"All who die by the way, whether by land or by sea, or in battle against the pagans, shall have immediate remission of sins. This I grant them through the power of God with which I am invested. O what a disgrace if such a despised and base race, which worships demons, should conquer a people which has the faith of omnipotent God and is made glorious with the name of Christ! "

Pope Urban the 2nd, Address to the Council of Clermont, November 27, 1095

"I'm fighting so I can die a martyr and go to heaven to meet God. Our fight now is against the Americans.

Osama bin Laden

The belief in a supernatural, unseen being, while the details of its expression in any one individual is varied, it is a very important factor in a group. Hence the use of differences in the details of that belief across groups is so easily manipulated to drive others to violence.
But it is, even more important for the phenotype than that.

For a person of faith/theist, it is part of their basic structure of reality and worldview. It is their sword and buckler against existential horror.
An atheist, a person who does not share this very core symbolic object "human universal" with them, is missing a major tag. No wonder they would not trust them. No wonder they fear them. For some of them, an atheist is a walking threat of combinatorial explosion.