Such as, seeing devils where no devils exist.
There is not a boogeyman under every bed.
No, that's not what he meant at all, he meant and embracing them and their works, like those who pursue interest in the occult.
But, since you mentioned it Sinkspur do you believe that demons exist, do you believe that roam the world seeking the ruin of souls? Since you stated that you believe hell may be empty I can understand why you reject the notion that reading books that romanticize the occult are harmless.
I disagree -- I think the devil makes it a point to be everyplace we look for him. And he's especially happy when we put him in places where he wasn't before.
That is, in fact, Rowling's whole point about the characters in her book not saying "Voldemort" -- they grant a power to his name as if it had the power of Voldemort himself, and it's self-fulfilling.