OP, you make a good point.
Isn't it interesting how the concept of 'witches'-still play a part in our infant/junior reading schemes?!
My DSs did, was it Oxford Reading Tree? And DS1, in Y2, brought one home, about a ghost. A little boy was racing through the rooms of their empty, newly bought house, when he encounters 'a ghost', a girl. She's cut her hand and is running from room to room, dripping blood. The boy helps her.
I totally expected a rational explanation- the ex-caretaker's daughter, etc. But no. She really was a ghost.
I made a comment to school, along the lines that I spend A LOT of time keeping my primary school DSs away from the concept of the supernatural....
Unlike my childhood where we were allowed to buy '10 great American Ghost Stories' , and something like 'The Puffin book of ghosts'- with our pocket money, aged 10, in WHSmiths, Salisbury.
'Dunwich Horror', anyone? (Look it up!)
My DSs are now young adults. Apart from one small, easily dispelled incident with DS2, aged 4, we've literally had no 'monster under the bed', 'ghosts in the bathroom' incidents.
However, I do understand the place of folklore! But that'd be me, telling my DSs about ancient beliefs in tree spirits, etc!