Paying people to review content costs money and that eats into their bottom line. Efficacy and political fallout are factors for sure, but "company avoids spending money" doesn't need much further explanation.
This is no different from a company using cheaper (and perhaps less safe) parts, using the cheapest call center they can (and letting customer service suffer) or any other way of cutting corners to save a few cents.
This is no different from a company using cheaper (and perhaps less safe) parts, using the cheapest call center they can (and letting customer service suffer) or any other way of cutting corners to save a few cents.