Human sacrifice, the Crusades, the Inquisition, Jihadist suicide bombers, extensive pedophilia and Intelligent Design do not commend organized religions to us.
However, like art, music, farming, city building and scientific inquiry, any ubiquitous, large scale, organized human behavior that persists for millennia, such as religious belief/ritual, is highly likely to have been selected for its adaptive value to the populations demonstrating that behavior. Lest we throw out the proverbial immaculate baby with the holy bath water, we should note that even though Wagner, Nietzsche and Riefenstahl were used to pump up the Third Reich, modern societies that suppress music, philosophy and film are rightly seen as not understanding the value of these evolved behaviors.
Human's evolved ability to empathize with others beyond our immediate family
units is likely of much more profound evolutionary value than our ability to
perform the abstract mathematical-like computational behavior called reasoning.
Religious belief and ritual have been powerful societal forces cohering diverse
populations into large self-identifying groups for millennia. 
Such belief and
ritual have been prominent in virtually every human group that successfully
cohered themselves into cooperating long enough to leave behind something
identifiable as a civilization. To consider such unfailing relationship to
successful societal evolution to be a misfiring of intentional stance seems as
spectacularly misguided as if one concluded that the evolution of the thumb was
simply an unfortunate replicating error of finger growth which we regularly hit
with hammers. Random chance is unlikely at work here.
The palette of evolved neurological responses from which such complex behaviors
emerge are probably similar in kind across most higher level primates. For
example: chimps do not kill each other, they share food in an organized manner
and groom each other. 
If they suddenly developed written language and we handed
one a tablet that said "Thou Shalt Not Kill", "Thou Shalt
Share" and "Thou Shalt Groom Thy Neighbor As Thyself" I suspect
most chimps would resonate deeply with the "wisdom" and "rightness"
of these truths which would feel so deeply true (since they would echo ancient,
species-wide evolved behaviors) that it would not be surprising if they
attributed to the author supernatural insight. In fact the church of Thou Shalt
Fly South in The Winter would probably attract quite a flock.
Before we try to foist upon the other 99% plus of humanity, reason as our main
hedge against Armageddon, I would suggest we contemplate the millions of years
of cumulative adaptations that have resulted in our present position (whether
you consider us the crown of creation or a planetary disease is irrelevant).
The fact that we are not still hunkering down in our caves, killing all "other"
groups on neighboring hillsides is not because of the evolution of our ability
to reason. It is more likely because of the mutation and selection of such deep
hindbrain responses as identifying all infant face-like images as "cute", even
other tribes', etc. The evolution of deep emotional responses that allow us to
see "us-ness" in others is likely many times more important in our evolution
into humanity than the evolution of the ability to reason. Reducing 100,000
years of physical/social evolution to an either reason or religion paradigm is
not only probably useless but I think wrong-headed as well. To paraphrase
Orwell"."Forebrains good, Hindbrains baaaad" is not the right paradigm.
Religious belief is not a rational decision. In fact, as has been pointed out
frequently, the question of whether or not whatever we define as objective
reality includes some "spiritual" dimensions/realm/aspects that exist beyond
what our scientific methods can detect is as unfalsifiable a construct as some
would say is String Theory. Therefore, the opposing null hypothesis is equally
unfalsifiable. And adopting a belief that there is no such "spiritual
stuffness" based on Occam's Razor or other aesthetic responses is no less a
religious belief than Voodoo (maybe more since some Voodoo beliefs derived from
the falsifiable reality of Zombies)
It is likely that the great majority of our behavior is governed by some
overarching, synthetic combination of conscious/subconscious/wholly unconscious
intent/motivations/drives/reactions resulting from a complex system comprised
of our forebrain, midbrain, hindbrain, central and peripheral nervous systems, etc.
whose synthesis has resulted from millions of years of evolution. Human's clear
innate proclivity to feel/believe that we are something more than animals
isolated in space and time from one another appears to have had strongly
adaptive value, probably because, as our perception of cuteness keeps us from
killing our progeny when they cry, feelings that we are more than our immediate
feelings of wanting your meat, your mate, your cave facilitated our ability to
cooperatively cohere into larger more successful groupings.
The important problems we all have with organized religion are not derived from
their belief in some "spiritual stuffness" but in the misapplication of the
social influence exerted by the religious groups. (In fact the Islamic Golden
Age shows that widespread loss of religious belief is not a prerequisite for an
age of scientific acceptance and progress) From jihadist violence to public
health conflicts to anti-science educational policies, it is not the belief in
unfalsifiable constructs that constitute the problem for most of us, it is the
societal policies/strictures/etc. that result. Trying to convince "them" they
are wrong about the unfalsifiable underpinnings of their experience:
1) Undercuts our credibility (since unfalsifiable is as unfalsifiable does)
2) Sets the world against us (telling the rest of the chimps they shouldn't
groom won't go down smoothly)
3) Is totally counterproductive (will result in even less influence to
positively effect the important societal factors impacted by religious belief)
Developing paradigms that can harmoniously modulate the deeply felt belief
systems of the overwhelming majority of humans towards more rational
behaviors/value sets is likely a more useful pursuit than the philosophic
equivalent of throwing our feces (pontificating abut how foolish such beliefs
are, calling ourselves "The Brights", etc.) E.g. one could conceivably believe
in the fundamental correctness of much of the major holy books and the
generally accepted Western scientific worldview if one could develop an
understanding how the tools a creator could use to create the universe as it is
are the physical laws of nature as we understand them. The less people
understand of science the more they are susceptible to being told by ignorant
demagogues hat there are irresolvable conflicts between religion and science,
hence it's time to pick a side. The more defensive feces throwing the
scientific community indulges in, the less acceptance of a scientific worldview
will likely exist.
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