This issue has been stewing for at least the last 5 years...
Mail is what the Postal Service does and it no longer "binds the nation…. through correspondence." Mail today is not a communications medium; it is a broadcast medium for businesses.
Indeed, from a 21st century perspective, the USPS looks like a hopelessly retrograde enterprise. We cut down trees, mill them into paper, print words on the paper, then transport the paper all over America in pollution-belching trucks, and have people deliver them (often on foot) to 150 million addresses. Then people throw most of it away unopened.