"The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one."
- The Catcher in the Rye, JD Salinger.
Shaming those who are posting selfies (of which I am not a fan) is counterproductive. Who are you to say that this person is self-centered? How do you know he or she isn't just posting a photo of his or her self post volunteering for 12 hours?
Silence does not equate to apathy. Just because some people are not as vocal about their volunteer work does not mean that they do not care.