This cracks me up. When I was first on Medium, I didn't understand, either, and left just one clap. But I caught on quick. People who PERSIST in the practice, though, may be suffering from Hypertension Non-Existence Syndrome (HyNES.) I've just made that up, but why not? Those people are simply too uptight to let their finger rest for more than a moment on that mouse button...
You know where I'm going with this. There are other buttons in this existence which do enjoy more than just one tiny second of being touched, and a decent person respects that.