Facebook shouldn't have to factor "this person is 5" into their decisions at all. Minors, in countries where Facebook can rake in the dough, can't legally own or use creditcards. The term whale is derogatory, and is a super great subversion tactic: its presence distracts you form paying attention to the real problem, and instead tricks you into falling over the word itself, ignoring the real problem. And hey, looks like it got the job done.