The god of the three major religions has a couple of traits: he is omnipotent, onnipresent, omniscient, omnibenevolent, timeless, formless and a few other mediocre ones.
Then why does evil, injustice, pain, suffering and murder/killing exist in such a 'perfect' world created by such a 'perfect' being?
According to logic, this can only be if god hasn't got one of the four 'omni-traits' or because he simply doesnt exist.
When asked why their god still hasnt used his omnipotent power to stop the devil, religious people will always answer in a few ways like: that it is according to his plans, that judgement day will come, or that god is sleeping all this time and can wake up at any moment (which doesnt make him omnipotent in the first place). Or religious people will answer this question by saying that without evil, good doesnt exist, so that the creation is still perfect.
Now, the truth of god's plan is that he has created the devil and humans as a scapegoat in his plans so people belief good actions are god and bad actions are godless and for the devil. Because god has created the universe according to religion, the only logical explanation is that god is ultimately responsible for his creation - not humans and the devil. And if god is the original creator of the devil AND uses him as a scapegoat, the only logical explanation is that their god is even more evil and 'imperfect' than the devil. But religious people will, off course, always deny this scapegoating.
This brings the logical consistency of these three major religions to it's knees. This proves that their god is either not omnipotent, omnibenevolent or non-existent.
These steps can never fully disprove that god's dont exist, but they can address the logical inconsistency of the god of the three major religions in a few very simple steps.
If one will now ask how I would've created an even better, more ethical world if I were a creator, I'll gladly explain in another comment as I think that is an even more interesting question to answer
