And thus we receive proof of why, nowadays, nobody can analyze texts and nothing is scary.
Reading comprehension, or at least higher-level comprehension, is the processing of knowledge presented and the drawing of conclusions not directly stated but implied in the text; for example, in Poe's The Fall of the House of Usher, it is widely agreed by those who examine the tale with an abstract manner that the two Usher siblings are actually depictions of Poe's struggle between his artistic side and his socially-accepted one. There is NO concrete support for this in the text as far as Poe saying "Oh and by the way the siblings are a representation of my inner turmoil", but there's little to no doubt that the story is actually about that.
Humans have an innate fear of the unknown, furthermore- hey! The entirety of /x/ is proof of this- and by EXPLICITLY STATING what something does, by god that just doesn't effectively prey on innate fear. There's only so much one person's imagination can do, while leaving certain aspects up to the reader/viewer always provokes more lasting horror and fear.