I know this is like a broken record, but lots of theists out there, Christians particularly in this example, just don’t have the slightest clue what logic is. I had someone argue that there is an objective morality because, assuming God exists, then such a morality is a characteristic of God.
Let’s look at an example of this. Let’s say you had never seen a cheetah, you had no idea what a cheetah was. I came to you and told you that one of the defining characteristics of a cheetah was that it ran really fast. You could ask me how I know this and I could take you to see a cheetah and you could see it run really fast. You could, and should, ask me how I know that this claim I’m making is actually true and it would be on my shoulders to demonstrate how I came to this knowledge. Even if I wasn’t able to take you to see a cheetah first hand, I could show you all kind of videos online, books, expert testimony, etc. And you could, and again should, ask how those experts came by their knowledge and the same rules would apply. Eventually, those experts would have to get back to actually having a way of seeing a cheetah in action or studying the structure of a cheetah or something whereby they could have rationally gained that knowledge.
Claims about gods don’t work that way. Theists cannot produce any rational means of coming by the information they claim to have, they cannot show that the gods that they claim are real actually operate the way they assert. There are no experts that can show that they have achieved such knowledge through any demonstrable means. There is no way of demonstrably differentiating between a real characteristic of a god and an invented one. You cannot go see a god and find out if the claims made about it are actually so.
This kind of thing goes right over the head of theists. There’s some circuit in their head that insists that their gods are exactly as they imagine them to be, they’re entirely unable to contemplate the possibility that they have no way whatsoever to know if their gods are real or what they might actually be like. In that way, it is exactly like an imaginary friend and that’s important.
Seriously, how many times have you had a theist tell you in complete confidence exactly what God is like and how God would react in every possible situation, but can’t explain how it is that they know any of this? Oh, they might say they read it in the Bible, but again, they can’t describe how the people who wrote the Bible came by their knowledge either. It’s just magic! Or maybe it’s personal revelation! Unfortunately for them, there’s no way of telling the difference between personal revelation and just making something up and again, they’re left with empty, un-demonstrable claims that nobody with the slightest grasp of reason ought to take seriously.
That’s probably why they buy into it. Zero reason skills whatsoever. And they wonder why we laugh at their absurd beliefs.