The ability of sociologists to study religion is closely related to their ability to self-examine and to self-criticize.
Therefore, the reason that sociologists study religion must have to do with classifying "us or them," as that study relates to belief in GOD.
According to Merriam-Webster on-line, "religion" means "the service and worship of God or the supernatural; commitment or devotion to religious faith or observance; a personal set or institutionalized system of religious attitudes, beliefs, and practices; a cause, principle, or system of beliefs held to with ardor and faith" http://www.merriam-webster.com/dictionary/religion
Since many in the contemporary world claim to be without religion, the antithesis of the definition of religion may be illustrative in either verifying or denying the claim that a human can actually "be without religion."
An anti-religious, irreligious or areligious worldview is "The refusal to serve and to worship God or the supernatural; commitment to eschewing devotion to religious faith or observance; a personal set or institutionalized system, (e.g. secular science,) of anti-religious attitudes, beliefs, and practices; a cause, principle, or system of beliefs, (e.g. evolution,) held to with ardor and faith, (especially in the direction, which is consistently away from a religion, either corporately or individually.)"
One needs look no further than Professor Richard Dawkins, who professes his personal belief about GOD, holding to this position without credible evidence.
“The God of the Old Testament is arguably the most unpleasant character in all fiction: jealous and proud of it; a petty, unjust, unforgiving control-freak; a vindictive, bloodthirsty ethnic cleanser; a misogynistic, homophobic, racist, infanticidal, genocidal, filicidal, pestilential, megalomaniacal, sadomasochistic, capriciously malevolent bully.” The God Delusion
Professor Dawkins has demonstrated that he is in fact the very individual that he alleges GOD to be, based solely on the level of vitriol, with which he makes his claims. "The universe we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil and no good, nothing but blind pitiless indifference."
Do sociologists study the hopeless world of Richard Dawkins, regarding his religious views?
On the one hand, Dawkins claims that the universe has "...no design, no purpose, no evil and no good, nothing but blind pitiless indifference."
On the other hand, he refutes his own argument by stating that the GOD of the Torah, the Talmud, and the Writings is a "...megalomaniacal, sadomasochistic, capriciously malevolent bully.”
Yet, in Dawkins' fantasy world of no right and no wrong the capricious assertion that GOD is a "...megalomaniacal, sadomasochistic, capriciously malevolent bully,” means that Dawkins himself must be labeled a "...megalomaniacal, sadomasochistic, capriciously malevolent bully,” based on the strongly emotional usage of slanderous terms, without a standard of right and wrong upon which to base his allegations.
Ergo, to be without religion, one must look like "a deer in the headlights," when the subject of religion is mentioned.
Sociologists must then logically affirm that one can only be without religion, when one is unemotional, regarding the subject of religion.
Individuals, who are allegedly-atheist in philosophy can never be without religion as long as they are as religiously anti-religious as is Professor Dawkins.
What are the findings of sociologists about religion to date? Some religions are basically peaceful. Some religions are basically warlike. Some religions are a distressing mixture of the two extremes.
On the other hand, those who may reject religious belief systems altogether, arguably base their lives on some form of logic and systematized thought, if they may be said to be intelligent at all. Some of these people are basically peaceful. Some of these people are basically warlike. Some of these people are a distressing mixture of the two extremes.
The problems of the world throughout the entirety of history are apparently extant in humanity as a whole, whether religion is part of the picture or not.
Sociology studies religion in order to ascertain the cost-benefits analysis related to the belief in GOD or the disbelief in GOD.