It's because of all of those things that make it tame. Those events make it hard for the reader to relate and therefore the psychological side of the horror is a lot downplayed here. I love Echo because of the psychological horror and unlike the other routes Leo's route is almost regular horror (which don't really scare me at all). It also doesn't involve the Echo mysteries much compared to the other routes, so if you play it first it doesn't give you that itch to replay the other routes to figure out the entire mystery.