I think its because for the most part (particularly for facebook), the interaction never really gets beyond the level of discourse during a visit to the checkout. A hollow greeting and perhaps a comment on some immediate concern such as the weather.
That this is amongst people who ostensibly know each other on some personal level - a so-called 'friend' - is quite sad.
World in chaosOf course, there have been an awful lot of other things occupying my mind of late - the disasters around the Pacific Ring Of Fire, North Africa, the collapse of western economies and so forth. After a while it turns into a sort of 'disaster porn' that you need a break from though. Having empathy for people's plight is one thing but it can become overwhelming and for nobody's benefit.
I'm pretty much convinced that people's plight is just misery anyway. The strong take what they want and the rest suffer. Seems to be the winning evolutionary strategy since we started agriculture, since before that the social groups were too close and small for cheating to win in the long term.