It's not just that this whole scenario is slimy. It's that Facebook was fully aware of it, had a nice in-house term for it ("friendly fraud"), and not only chose not to approve refunds but also chose not to implement the most basic measures to prevent it.
[edit: as a commenter pointed out, the term “friendly fraud” predated Facebook]
This is symptomatic of a corporate culture that is toxic to to the core.
The money quotes are in the 2 paragraphs below:
"In 2011, Tara Stewart, a risk analyst for Facebook, studied the issue and suggested that the company begin requiring users to enter the first six digits of a credit card used for payments on certain games. Stewart ran a survey of Facebook users and found that many parents were not aware that Facebook stored their payment information after entering it one time. They also found that the kids weren’t aware of what they were doing. “It doesn’t necessarily look like ‘real’ money to a minor,” Stewart wrote.
She ran a test to see if the entering the cards first six-digits would reduce these unwanted charges and the results were encouraging. She also said it would “make sense to start refunding for blatant FF-minor.” The abbreviation “FF” stood for “Friendly Fraud,” the term Facebook used to refer to these fraudulent purchases which were made without malicious intent. Despite this obvious solution, Facebook decided that it would harm revenue and elected to continue fighting refund requests for the foreseeable future, the documents show."