To me, "survival horror" means a genre where the "horror" isn't subtle, creeping, or impending.

It's HERE. It's battering down your door. It's chasing you through the streets. It's eating your next-door neighbor.

The goal isn't to discover what lurks in Ligea's tomb, or to uncover some Lovecraftian horror that man was not meant to know.

It's getting the hell out of wherever you are and getting somewhere where the "horror" ain't.

It's unsubtle, but perhaps taps more into man's primate fears of having to escape from being eaten/killed by a predator.
"...so, right around there a negative stigma was attached to the idea of surviving on human flesh. Still, there were isolated groups of zombies that --" (Miss Bitters, INVADER ZIM)