My stance on the Resident Evil vs Silent Hill discussion:
My stance on the 'Is Bloodborne/Resident Evil 4/Whatever a horror game:
Scariness is subjective, so in actuality Scary =/= Horror. Hell, there are things that scare us that are not horror. Horror in terms of entertainment media has created a life of its own over its course of creation by building on-top of itself. It has engulfed a number of seemingly unrelated things that create a withering mass of possibilities. Resident Evil 4 & Bloodborne are both action games, but so are many horror games. But they're both definitely horror games. Yes in Resident Evil 4 you shoot mad farmers until their heads explode (and possible plagas parasites burst out). But it plays like a more 'extreme' version of one of the older Resident Evil games as it were, and definitely tries on numerous occasions to make the player go through the unexpected, the morbid, and face intense odds, as well as scenes to tense up the player, scare them, and send them on an emotional rollercoaster. It is a Horror-Action game, which is still a horror game. Being an action game doesn't immediately mean it is also not a horror game.
Bloodborne is in a similar vein. It pulls from all sorts of horror literature, most notably Lovecraft, and deals with both the Van Helsing-esque vein of horror (which is also horror anyways), and the concepts of Cosmic Horror from Lovecraft. Gameplay puts you at odds even as a powerful being, and brings you along a dark and horror-inspired world to eventually deal with growing madness and chaos. It is an Action-RPG, but it relishes in is themes, atmosphere, monstrosities, and as a previous post explained, nails a lot of what it goes out to do.
I think Horror can be sometimes hard to define, but something important I think is audience response, creators intent, and the growing form of horror as an entertainment media, and all of the different tropes, subgenres, and styles that is has been created under it, others have then copied, imitated, been inspired by, and then gone forth and created works under the same demeanor. As such, the definition of what can be horror does grow, and it has many factors. I do thoroughly believe that Horror can be attached to anything, like comedy, but obviously not everything that has some horror traits are horror. This said, Resident Evil 4 / Bloodborne I think obviously pull a lot from horror, both have a lot of horror moments and pillars of survival, atmosphere, a dark world, which is put together through stand-out moments, and powerful characters in a chaotic and downfalled world of monstrosities.