If you believe someone "designed" religion, then you're just as dull-witted as Zionists, Fundamentalists and those who believe, generally, in Chosen Races under Him, those who believe God demarcated a set of concrete objects to which they were and are perpetually given sole ownership. That is, you accept the story of "God-as-Big-Brother," but you voice it in the negative, whereas they voice it in the positive.
I think a large more of "why religion at all" can be explained under a Human line of thought. People follow custom and habit, and this leads them to accept their inferences as valid. Prayer becomes "valid" in a religious sense because of confirmation bias and human ignorance. There's no such thing as "rigorous prayer." Prayer has not been tested in the way scientific hypotheses are tested. But between event of Prayer and event of "receiving an answer," many religious people are satisfied with the communal aspect of religion. Then people will see their prayer actualised, given they give God his "Way" (time frame).
Anyway, we could investigate various aspects of why religion at all. It's purely psychological, but is it because people "like to have explanation"? No. They are not explaining; they are telling a story. It is a "closed explanation" that seeks not to integrate with other explanations. Does this explanation actually eliminate the "void" feeling? Well, we still have to answer why so many other wildly contradictory explanations (scientific perhaps) also eliminate that void feeling, supposing there ever really is one.
But at bottom, religion was not designed by an agent. Here, we agree. Religion cannot be coherently said to be designed by "evolution." So perhaps the psychological answer reduces to evolution; but there's still debate over the status of evolutionary psychology and evolution as the scientific theory. It's a long debate.
Short answer: Why religion? It's part-communal / part-individualistic. We like to tell stories in our community, we each of us. Sometimes our stories delve into metaphysical claims, sometimes they are contrary to science. But even science is sometimes contrary to science. Why this religion as opposed to that? Why all the specific religions? Well, why so many colours in the set? Why are trees brown rather than pink? Seems like the same kind of question to me.
Problem is: God does not do these things. People tell us that these are the things God has done (flooding, divine imperatives).
God doesn't do any of that stuff. People interpret God's actions as having those intents and manifesting in that way.
They call a lightning bolt "Zeus' wrath" whereas I call it an electrical discharge from the Earth's atmosphere. Zeus never existed; God never existed. People who said these things "exist" did exist.
Basically, don't attack God when you should be attacking people who put spin God's actions. "Good" spin, "bad" spin. It's all interpretation, and it's all fucking stupid.
