Well, aminozuur is pointing out hypocrisy. Facebook is not applying the same rules to everyone. That is bad. That aside, my own views are similar to sep_field's... with the exception that I would silently prefer Facebook to go away, without explaining why I'd like that.
Given that “Whataboutism” really means “hypocrisy in a geopolitical context” I think the entire definition should be updated to reflect it as a very valid observation, instead of the assumption that it is a weak argument because in my experience it usually isnt, even during the height of the cold war the Soviet Union’s observations about the US were accurate.