I understand your point about the number of people who die, however, a lot of those bodies are disposed of in a way they won't be found (I not sure exactly where you are in the series, so I won't spoil anything for you), so most of them are "missing persons" rather than murders. And at least a couple (two major deaths in season 1) are made to look like accidents.
Which is still obviously suspicious, but given that some of them are from out of town, some of them are transient (due to the vacation destination/seasonal worker nature of the town) and some are involved in stuff (drugs) where them dropping off the face of the earth isn't surprising, I don't think the body count (which I think is 20 or less) is THAT ridiculous.