The same reason that people say you should drink more water, or get more exercise, or get more sleep, even though there are people who are drinking too much wat

The same reason that people say you should drink more water, or get more exercise, or get more sleep, even though there are people who are drinking too much water already, destroying their joints with too much exercise, or are getting far too much sleep. It helps the common man, who isn't doing enough of these things, and that's enough for it to catch on.