If the Bible says Jesus is the only begotten Son of God, but the Quran says God neither begets nor is begotten, then, at best, followers have no choice but to agree to disagree. At worse, they can have a war to decide who is right. — Art48
Why is their disagreement cause for such alarm? The pages of this forum are filled with disagreement.
Religions’ epistemological method is childish. Mommy or Daddy is the way children decide what is true and what is not. If my Mommy says a politician is golden but your Mommy says the same politician is human crud, then we have no choice but to agree to disagree. At worse, we can have a playground fight to decide who is right. Religion’s epistemological method is fundamentally the same as the child’s epistemological method. — Art48
You might say there is a foundational belief the faithful adhere to that the unfaithful do not, but you can't then say that the theology that follows is not subject to criticism and debate within the particular ideology. While you may find some particularly fundamentalist belief system that relies upon one or a small number of prophets to decree what is right and wrong, that doesn't describe religion generally, but just some particular ones.
The point being that you're rejecting religions that insist there is one simple reading of a particular sacred work and that it is not subject to debate or interpretation, but that criticism only works insofar as you choose your religions to criticize.
What epistemology do you use to determine morality? I would suspect it is not the scientific method. I ask because it is very likely that the method you use varies little from the ones used by religious systems, which, as you note, is reliance upon historical wisdom.
This is the situation we should expect if God does not really exist: different civilizations making up different stories about God. — Art48
The other option is to acknowledge that you're not the first to realize this and try to figure out how a rational, non-deluded person could resolve this. Otherwise, you posit yourself as a special someone who was able to see the emperor wears no clothes where others could not.
So, if I'm Christian (and I'm not), I would have to admit it seems that my belief did not come from an exploration of all religions, and by the force of logic, I fell upon Christianity. I would have to acknowledge the incredibly strong correlation between the belief of my family, my community, and my larger society and my beliefs. That is, is seems Christians beget Christians and Muslims beget Muslims. So, if I'm that honest, I must take the next step and ask why I insist upon Christianity's myths and not Islam's. The reason is likely that it comes to me with a certain credibility that I am willing to take seriously (where I am not willing to take others so seriously), and from that, more significant truths can be found. Will all the truths found from Christianity ultimately mirror those of Islam? Doubtful. The question though isn't whether I'm exploring trying to convince others who disbelieve, but it's whether I'm exploring trying to find what resonates with me, which then must allow me the ability to reject those conclusions in conflict with my other beliefs.
What is going here is not a whole lot different than what you probably do when reading one philosopher or another. Maybe your views are closely aligned with Kant's, so much so that you declare yourself a Kantian, read Kant's works closely, debate Kant, find subtleties within his writings that you insist you better understand than others, etc. And, occasionally you realize that what he just said was bullshit, so you reject it, but you're still a Kantian.
And what makes Kant so believable and credible? It's not the scientific method to be sure, but it's some other epistemological method being employed, but it's not the sort of epistemology you described in your OP, which is that you see Kant as your parent who tells you what to do. Maybe there is someone who actually uncritically accepts everything Kant says, but that's not an interesting person to speak to Kant about, and it doesn't give rise to a reasonable argument that Kantians are like uncritical children. In fact, I would suspect a Kantian to be the opposite of uncritical, but to be of a philosophical mindset, else he'd be doing something other than reading Kant..
: religion gets us started on the path, but eventually we realize it’s fictional. At that point, we arrive at a fork in the road: atheism lies on one side, a personal search for genuine knowledge and experience of God lies on the other. — Art48
You miss a key distinction between fiction and fraud. If you read A Christmas Carol and your primary criticism is that you've searched the world over and could find no Ebenezer Scrooge or Tiny Tim, I don't think you followed the purpose of the story. It is no doubt fiction. That you decided to treat it as a non-fiction narrative is your misstep. It can only be considered a fraud if you personally start with the notion that it attempted to take itself literally.
If you want to criticize those religions that do that, have at it, but that would be a criticism of certain religions and not of religion generally. That leaves open the possibility of accepting religion, but denying the very simple criticisms you assert in the OP.