There are about 73 million children in the US. I'm going to go ahead and bet that even though you don't personally know one who uses facebook, quite a few of them in fact do.
Probably - but just a poll of my middle schoolers class and I can guarantee the mention of Facebook will get blank stares. Insta - yes, that they’re familiar with.
What they use most is TikTok and Snapchat. My point being the harmful marketing cannot be proven if hardly any children actively use it