(The Congress shall have Power) To establish Post Offices and post Roads;

Nothing here that says the government has to pay for it so it could be privatized or made self supporting.

Confederate constitution:

(The Congress shall have Power) To establish post offices and post routes; but the expenses of the Post Office Department, after the 1st day of March in the year of our Lord eighteen hundred and sixty-three, shall be paid out of its own revenues.

This clause pretty much mandates privation or self-supporting.



  

In today's PC environment telling the truth is now considered hate speech