if atheists want to be honest, they would say, "If I believed, Christianity would be the true religion because other religions are filled with satanic imagery."
I disagree. If an atheist were honest, they could well state that if they believed (in Christian doctrine), then whilst they might under such circumstances
believe Christianity to be the true religion, they recognise that their believing it to be the true religion does not actually
make it the true religion.
Reality is what it is. It is not (necessarily) what you, I or anyone else here believe it to be. It existed long before we were born, and will go on existing long after we are gone; and what we do or think is
utterly inconsequential to the question of how reality actually is. If it is a reality absent a divine entity, it remains so
no matter how many humans on this speck of rock believe it to be otherwise. Likewise, if it's a reality underpinned, managed and/or maintained by such an entity, it would remain so
no matter how many humans on this speck of rock believe it to be otherwise.
As such, you appear to be advocating not honesty, but wishful thinking.
Instead they argue, "All religions are the same!"
That is dishonest.
It's an opinion. And probably a superficial one: as it happens, it's not an opinion I share (and I suspect that not many atheists would share it either, were they to delve deeply into the myriad religions that exist). I think some religions are "better" than others, for one reason or another. Culturally-inculcated subjectivity is almost certainly one factor. There are plenty about which I have no opinion, either because I don't know they exist or because I don't know much about them.
Just because you guys don't believe in Christianity doesn't mean you can't admit that it would be the true religion if you did believe.
No-one is under any obligation to admit such a thing; if they did, it would be faulty reasoning. Reality does not reshape itself to become in accordance with our wishes, desires, or firm beliefs. If I believed Christianity to be the true religion, my mere belief does not elevate it to the status of "true religion". I could still be wrong. The Jews could still be right. And nothing that either you or I believe or hope or desire would matter one whit to that.
The same is true if there is no transcendent divine entity at all. The atheists would still be right (even if they got there by what some consider a hasty conclusion). No matter how strongly you or I or anyone else believed, we'd
still live in a world absent any such transcendent divine entity. The only "divine entity", in such a circumstance, that would exist would be the one in our imaginations.
In fact, I even got an atheist to admit this to me a few years ago. He sat down with me and I showed him all the occult and satanic symbols of other religions and he said, "You're right. if God is real, Christianity would definitely be the truth. I just don't believe in God."
That's not exactly bulletproof reasoning, there (which God?), unless you're omitting rather a large chunk of the tale - and it's also not the same statement as the one in your first sentence that you're railing against atheists for their failure to accept.