There's also an option on FB not to share your wall posts with anyone. Yet you'd not infer from that that people sharing crap about their lifes on the wall is not integral to the FB's business model.

Something's wrong with your logic.

FB serves ads. Robinhood doesn't. So, it's not clear how in the world people's history would be integral to their business model. I suppose we could imagine them using it down the road to offer credit or something. But as of right now, it is a mere insinuation without a shred of evidence.