Private companies are required to fully fund pension plans under Federal law. What's specific to the USPS is the requirement to fully fund health care benefits

Private companies are required to fully fund pension plans under Federal law. What's specific to the USPS is the requirement to fully fund health care benefits and, more importantly, a restriction preventing the USPS from lowering health benefits for existing retirees.[1] Unlike pensions, health care benefits are normally not considered vested benefits and so when faced with the USPS' dilemma any other organization, public or private, would simply lower health benefits. The USPS is being screwed, but it's more complicated than the memes thrown around in public discourse. Your link doesn't give enough context necessary to debunk many of those memes and to resolve the confusion. [1] Also the Treasury bond thing, but that's not nearly as much an existential burden as health benefits.