If there was a super powerful being who wanted every human being to know that it existed, we would all know that it existed. He could speak to everyone in their brains in their own language, and explain his existence and what he wanted from us. He could change every tv show and radio program and book to explain his existence. He could put the information on the internet and on every cell phone in the language that the person looking at it understood.
Any number of ways to communicate to everyone efficiently and accurately. There would be no doubt, confusion or debate about it unless that being wanted people to have doubts and confusion. If Catholicism had been all that and a bag of wafers, there would never have been any other religion after it arrived on the scene. There would be only the one religion and it would be as obvious as the existence of the sun.
The true religion should have easily smashed all the competition. It would be impossible (or at least extremely difficult) to defeat the efforts of a supernatural being with something like "sin", "hard-heartedness" or disobedience. No need to wipe out the planet with sh!t like a global flood only to have all the bad people come right back. How could a weak ordinary human defeat the efforts of a supernatural god? It would be like a toddler trying to arm wrestle the Hulk. There should not be hundreds of different religions-- unless god wanted there to be all those alternatives to trick people into hell. Bwahahahaha!
But this is not the case. The supposedly one true god has acted exactly the same way as all the fake gods that people no longer worship. Inefficiently, slowly, capriciously, and inaccurately. The god(s) appear to one special guy, who goes around telling a few special people and there is all this magic, so they tell other people and eventually someone writes some stuff down.
With each retelling and translation and cultural adaptation, the message changes and gets more complicated, until nobody is practicing the same religion as the first group. And amazingly, the magic disappears right about the time people start to use critical thinking and science. Gods in these days of cellphone cameras and youtube are conveniently invisible and work in mysterious ways. They answer prayers at the same rate as random chance.
Would the most powerful entity ever, who created the entire universe, have to communicate by a primitive form of the telephone game? He can be defeated by a talking snake and some fruit. He maims and kills and destroys sh!t. In order to understand him, each generation of believers has to create thousands of pages of new explanations.
We have to conclude that either there is no supernatural being, that it is an evil SOB, or that it has no interest in human beings at all. Clearly, it wants the world to be exactly the way it is, with hundreds of religions, lots of problems that people have to solve on their own-- and many unbelievers.