alt Hacker NewsRather than asking him the question of why in a simple rudimentary form, give the guy motivation to quit facebook instead. Facebook employs guilt tactics about people they know to get them to stay, and if they quit, they're likely to go back because of in person connections. By sounding condescending, the person you're replying to is likely to justify staying rather than quitting.
i think your advice would apply in a standard human situation where optimal communication requires decoration, in this scenario i reciprocated the communication format which indicates acceptance