Not currently religious, but my understanding at the time was not that he didn't think things could be evil, though obviously we might see things like death as "evil" and he might not. It's that in order for us to "deserve" good things, we need to prove we are worthy. The only way to prove that is to allow us to do the wrong thing so that we can of our own free will choose the right thing instead. The question would then be why would you create beings with free will knowing some of them will inevitably suffer forever and the answer is generally "I'm god, who the heck are you to question me?" or some stupid explanation about how free will existing is itself a good that god did and therefore even if we choose evil every time we make a choice we are still engaging in a universal "good". Religions do obviously differ though, so everyone likely learned things a little differently.