The sad thing is I think they do know about the dangers, but choose to post Margot online anyway. They both know that the small amount of engagement he's got would disappear completely if he stopped showing Margot. He has no talent, he isn't a screenwriter, no one asks him to present or appear on anything anymore, and Sarah doesn't have a real job. Whether they want to admit it or not, they are using their daughter to feel like they have a job and to make money. It's so wrong.
Also, I've heard him say a few times this argument that everyone is so lovely about Margot online but he'd stop posting her the second anyone said anything bad. Okay, so as a father you want to expose her to potential danger and only if something bad actually happens you'll stop showing her after the bad thing has already happened? That makes no sense to me.