That is a good point, and an even greater tragedy.
This actually reminds of the military, which is another service that provides a way for people to escape tragic home or community situations for a new situation where they might find a sense of shared purpose and unity.
Pacifists and others opposed to US militarism would likely also say that anyone participating in the military is perpetuating evils and insist there must be a better way to escape these situations that also aligns with their sense of morality...
Really all these exceptions exist and are absolutely valid (imo) but I'd be curious what percentages we're talking about here... what proportion of people would be dead or worse off (vs alive or better off) today if not for the existence of FB?
For everyone in a who found their sense of community online, how many found contempt and ostracization from a mob 1000x the size of their physical community? How many physical communities (and families) are being divided along lines drawn up by online communities?