The entire "profit" argument is a red herring anyway. No other federal government agency is expecteded to make a profit. There's no rational basis, other than so-called conservatives' decades-long push to privatize everything (and thereby enrich themselves), to think the USPS would be profitable. How much profit does DOD earn? DHS? Zero, exactly the amount USPS ought earn.
For a long time those same "conservatives" have proclaimed "government should be run like a business." That's a load of BS. Businesses are operated for one and only one reason, namely, to make money for their owners. Government is established to serve the people, and for no other reason.