The degree of harm is correlated with the degree of use, just like cigarettes. If you smoke a handful of cigarettes a year, it probably won't affect you much at all. But if you use cigarettes multiple times a day for years, you'll do real harm to yourself. That's exactly true of Facebook. Yes, if you occasionally check in and are diligent about how you use facebook, you might escape harm. But unlike sugar, this slight-of-hand language they use of "human connection" doesn't prove that any facebook use is beneficial.
Sure, candy technically has calories. But the fact that human beings need calories isn't a good argument for eating candy. You can also get calories from healthy foods, and you can get "human connection" from, you know, talking to people, or sending text messages, or reading reputable news sources. Not coincidentally, the idea of a "social connection" was and is also a big part of apologizing for smoking as a habit.
