I still don't get why being potentially wrong a thousand iterations is more logical than being wrong on just one.
You're assuming that the standard is wrong, or that the bar is too low. If that's a given, then the logical course of action isn't to keep the standard and arbitrarily filter the results; the logical course of action is to recognize that the standard is wrong and try to come up with a better one.
Just because a bunch of things meet a criteria, it doesn't follow that all such things must be believed if you believe in one of them, especially if it would involve contradiction and if it would be unnecessary. (E.g. Believing in multiple gods plus the One God, or if you only need to a god, any god, to exist as your First Cause.)
If I ask someone why they believe in their god and they give their justification, I would expect them to accept every single thing that fulfills that justification. If they're unaware of something that fulfills it, I would expect them to accept it as soon as they learn about it. If they don't do this, then their stated justification isn't their actual justification.
You also are assuming that all the gods are on a level playing field, that they all, to this person, have met the same criteria. That's unlikely to be true.
All I'm assuming is that the person I'm talking to has laid all their cards on the table. I'm assuming that they've accurately described the justification they used and haven't left any criteria out.
The problem of someone being dishonest or cagey is a separate issue to what we're talking about.
From the outside looking in, probably not.
But it would be internally consistent.
Lots of false ideas are internally consistent. Internal consistency is necessary for a belief to be justified, but it isn't sufficient.
How is it irrational to define God as being a unique being, with there being only one?
It's begging the question. It's an attempt to define a particular God into existence.
Or, in another way of looking at it: it suffers from one of the problems with the ontological argument: existence isn't an attribute; it's a claim. Defining God as "a unique being" is really a backhanded way of making the claim that no other gods exist, which is a claim that needs to be justified on its own merits, not just implicitly accepted as part of a definition.