Of course they have a duty to protect children or at the very least not knowingly market to children. But the complaint here is that the headline implies that

Of course they have a duty to protect children or at the very least not knowingly market to children. But the complaint here is that the headline implies that it means something that they used the term whale. It doesn't. Whales are just a segment of customer. And incidentally, there are real, legit whales. There are a lot of rich people in the world who willingly throw money at luxury items like exotic cars, expensive vacations, lavish parties, etc. And some of those people like to play video games too and are totally content spending $500 or $5,000 on coins and junk for a game. Basically there are two ways to interpret this story. One of them has Facebook salivating while asking themselves, "Is this kid a whale?" The other interpretation has Facebook asking themselves with some degree of concern, "Is this whale a kid?"