I've been talking with fans from other sites, and I think that people underrate how important the disturbing imagery is for fear in this series. I believe it's just as important as the psycholgical horror aspect.
Why do I bring this up? Because I've run into so many people who believe that all the games have going for them is psycolgoical horror.
Yes, the series does have a good deal of psychological horror in it, but that's not the only thing scary about it. People say "The games really get into your mind. They're not like those crappy violent sadistic American horror movies!" like 6 out of the 7 didn't feature blood everywhere, tons of dead bodies with no purpose to the story, sadistic torture and treatment of people (especially children), monsters representing sex, childbirth, murder, and dark secrets, human sacrifice involving burning people alive, etc.
The series has always had this stuff! Yes, it has psychological horror elements, but disturbing and macabre visuals and atmosphere are just as much a part of it. If the series was exclusively a psychological thriller (as Vatra has called it), we'd probably get something more like a David Lynch film but without the monsters. I love being psycholgically disturbed. I loved the voices in the attic in 2. I loved the sillouhette of Adam in the basement of Homecoming. A lot of people say that they also liked the cat jump scare in one. But aren't they also scary because of what could be there. That what is there could appear beside you and possibly attack you?
The scariest moment in the series for me in when Heather was entering the Otherworld of Brookhaven hospital. I thought I beat the level and was about to meet somebody that could help me. God, was I wrong. Going in that eerie red room with the doors closing behind me, trapping me. Hearing the sounds of monsters and seeing Valtiel in the background terrified me to the point of not wanting to play anymore. I was very scared I would have a nightmare that night. All of that was thanks to the disturbing imagery.
On the opposite end of the spectrum, the lack of anything remotely disturbing is why I consider Shattered Memories the least scary Silent Hill game. I knew I couldn't be hurt. Everything was normal. It was atmospheric, fun, and a unique experience, but it wasn't scary.
I think what happened is that some people considered Homecoming overly-violent and some of the more conservative fans said "O, that's not right. The series never had very much violence in it. There was a lil gore here and there, but it was always about what you can't see" even though there was always gore and blood, and if not that, disturbing and horrifying imagery (Yeah, it usually is about what you can see).
SPOILERS FOR HOMECOMING BELOW
I'd wager that what the Orphanage did to the children in the water prison was more sadistic and horrible than what the parents did to their children in Homecoming. At least most of the Shepherd's Glen children ha decent childhoods and were loved. Yet, Team Silent worshipers consider it cruel in Homecoming yet genius in 4.
Again, there are instances of psychological horror and being scared of what you can't see in the series. But the disturbing imagery and monsters are just as much a part of it. You're scared of what you can't see, one of them being that a monster might be in that darkness. Harry was scared of what he might find in that locker and many of us were probably thinking of a monster.