Re: It's all about the money
"Advertisements are a halfway house."
In most jurisdictions, advertising has rules. Yes, they can be misleading, but they can't be outright false.
As an example, Red Bull settled a false advertising claim as the product didn't give anyone wings, and the claims of improvements in concentration are not backed up by evidence.
Since Facebook/Google et al are the ones selling the ad space, then they are liable for not making outright false claims.