Not true. USPS is self financing and does not use tax dollars. It never has.
It is mandated to self finance, and the reason it cannot right now is because mail volume has dropped so much with electronic messaging and transmission.
Although the Postal Service does not obtain direct federal appropriations (with a minor exception), its claims that it receives no government aid are deceptive because they ignore numerous, valuable implicit government subsidies. Unlike private-sector businesses, the Postal Service never owes federal income taxes, state and local income taxes, state and local sales taxes, or state and local gross receipts taxes; it is exempt from inventory and property taxes on assets it owns; and it pays a low-cost alternative to the unemployment tax. The government also subsidizes the Postal Service by granting it numerous regulatory favors and governmental powers. Some of the most important ones are exemption from motor vehicle licensing and registration requirements, immunity from parking tickets, exemption from local zoning and land use regulations, immunity from antitrust laws, and power of eminent domain. Moreover, the Postal Service's government connection enables it to borrow at a subsidized interest rate. The Postal Service's indirect government subsidies, which are sweeping even compared to those at other government owned or sponsored businesses, hide financial weaknesses at the agency and are a drain on government treasuries at the national, state, and local levels.This report estimates the magnitude of several of the Postal Service's hidden government subsidies and finds that the total dollar amount may exceed $1 billion annually. The report estimates that, on the Postal Service's operations in 1997, its income tax exemptions gave it a subsidy of approximately $500 million, about $415 million from the federal government and about $75 million from state and local governments. An estimate of the Postal Service's total income tax, sales tax, and property tax subsidies in 1997 is $1.2 billion. Moreover, because these estimates omit some tax and regulatory benefits, they understate the full amount of the government aid. If the Postal Service had lost its subsidies—that is, if it had been treated comparably to other businesses—it likely would have been forced to report a loss in 1997.