The context for the New England vampire lore was in the fear of tuberculosis. This disease caused victims to waste away as if their blood was being drained, and medical science couldn't cure it. Even though country people were frequently aware that it was just supposed to be an ordinary disease, the lack of a cure fed into ancient fears. Some people weren't completely convinced that science had the answers, especially when victims would report having creepy dreams in which their own dead family members came back to drink their blood. If your oldest daughter dies of tuberculosis and then your youngest daughter comes down with the same mysterious disease and starts having dreams about her dead sister being a vampire, what do you do? Listen to the doctors, who admit that they can't do anything- or destroy the vampire?
Here's the creepy part. They didn't actually call these monsters vampires, nor did they have any other local term for them. They apparently thought that draining the blood of the living was just something dead people did sometimes- unless, of course, the living stopped them.