Because the media leaves their parents basement once in a while and notices in every direction in a reasonably populated area that there is either:
a) multiple conversations that the word facebook comes up every 3rd sentence
b) sees someone using their internet connected device (ie - smartphone, Ipad, DSi, netbook, etc) on facebook.
My suggestion is leave the house once in a while.
The best way to avoid responsibility is to say, "I've got responsibilities."