What is a person supposed to do, if they happen to believe in God? Pretend that they don't?
No. But that's immaterial to whether or not a god belief can be rationally or empirically justified. Remember, I'm not asking you to give up your god belief. I don't even recommend it. I'm just saying that you, like all other Abrahamic theists, come to your belief by a method that doesn't generate sound conclusions - faith (insufficiently justified belief). You don't have to defend doing that to me. I have explained that not only do I not mind what others believe if their beliefs don't bleed into my life, I would consider leading you away from them unkind. I have no fear that that will happen whatever I write.
I write it to show you that your definition of rational is not the same as that of critical thought. You call beliefs rational or justified without them meeting those standards, the standards atheists use to conclude that the evidence for gods is insufficient to justify belief. If you learn and apply those rules, the only possible rational conclusion is agnostic atheism. If you've come to another position, you've made a leap of faith, including if you're an atheist who says that there is no god or gods. That is also not the conclusion of any sound argument.
You may call it "a whim" if you like, but it relies on rational inference of circumstantial evidence.
I disagree. You keep saying that, as do many other believers, who also describe their thinking as critical and their conclusions as rational, but one can identify and name the fallacies in their thinking. Everybody who claims that they have evidence of god sufficient to justify belief is unaware of what that would be. How do I know? They point to evidence consistent with a godless universe. They point to scripture that could have easily been written by men. They point to a cosmos that scientists describe without reference to gods. If that cosmos were evidence for a god, the god would appear in the theory to account for it. That's the ID people were looking for - a finding that required intelligent design, irreducible complexity. If one finds a biological system that could not have arisen stepwise through a series of beneficial mutations, as would be the case if a dog gave birth to a non-dog without human intervention (or any other find that falsifies Darwin's theory), then you have compelling evidence for an intelligent designer.
But they don't have that, yet call what they have evidence for a god anyway.
Some people see reasons for disbelief .. lack of empirical proof, for example .. and others see reasons for belief, such as believing that Jesus and/or Muhammad are who they claim to be. There is no "one size fits all", as you suggest.
Yes, I know. We don't all process information the same way, and thus have different beliefs about what is true about the world. My point, as you likely know by now, is that there is only one method that connects evidence to sound conclusions about its significance. Take that path, and you're an agnostic atheist. Use any other method and hold any other belief because of it, and you arrive at unsound (insufficiently justified) beliefs
If there was no evidence of God, then how could I believe
By faith, like every other theist. I have the same evidence you have, and it takes me to agnostic atheism, like everybody else trained in critical thinking. It's a method or pathway, like a recipe is a path from ingredients to an entree. There's not much wiggle room there if one wants to prepare the dish properly. I watch a show called Bar Rescue that you may have been seen. Outside experts in business, mixology, and food preparation rescue failing bars.
The bartenders are generally all over the place with their drink recipes, and the drinks don't taste the same or good - too strong or weak, too sweet or sour, etc. Then they learn a protocol connecting ingredients to a finished bar drink, and if they can stick to it, they all make the same drink and it's to perfection. This is analogous to the information processing we're discussing. Do it according to the rules of critical thought, and you end up with the same sound conclusion as others. Start improvising and come up with other beliefs, all different from one another, like the drinks made by undisciplined bartenders.
You might enjoy this (7-minute) video of a bar rescue, where the expert mixologist is first testing the crew on their margaritas, and then giving them a recipe to follow so that they all produce the same perfect drink every time, just as critical though produces sound conclusions every time if done according to protocol. The drink lesson occupies the first two minutes, then the consulting chef does something similar for the kitchen staff. Excellence and consistency is the goal there as it is in critical thinking:
I just can't believe that. It is not that I don't want to believe it.
I had written, "Eventually, one becomes comfortable with the idea that the universe may contain no gods at all, and then face and eventually accept the very real possibility that we may be vulnerable and not watched over and that consciousness ends with death." OK, but hopefully you recognize that as limitation. Others can accept that possibility. They realize that that might be the case, meaning that their thinking is more flexible and more consistent with pure reason, which allows for that possibility.
Not everybody believes in God due to tradition only.
It doesn't matter what reasons people give for believing in gods. They are not sound arguments. Maybe you might give that idea a little more of your attention. Is it correct? If so, does that matter? If you know that it is not - that there is a sound argument that concludes, "therefore God" - you can present that sound argument here.
You shouldn't assume that all believers make "unsound conclusions", just because you are aware of many that do.
I've told you why being a theist is an unsound position in every case. If you would resolve that as I just described, and realize that you have no such sound argument for gods, you might stop implying that you or any other theist does. There is no such thing.
Perhaps it is enough not to dismiss the possibility that God exists
Do you think I have done that? Do you think that I believe that there are no gods? Most theists make that claim about atheists no matter how many times one shows them that the opposite is the case, as I have done (options [5] and [6] in the previous post). Hopefully, you know better.
Would you say that you have dismissed the possibility that gods MIGHT NOT exist?