Should God have to make everything clear?

One theme of atheists is that if God were to exist, he would make everything clear, and there would not be a multiplicity of religions. Why think a God, if God existed, would make everything clear. If everything were clear, we would have no real choices. There would be one choice, and all other choices would be punished, and everyone would know what that punishment was and do the right thing for selfish motives.