Sixteenth Amendment:
The Congress shall have power to lay and collect taxes on incomes, from whatever source derived, without apportionment among the several States, and without regard to any census or enumeration.
They know this, they are fully versed in the law(tax protesters always are). They refuse to admit it, they refuse to submit to the law like everybody else, and eventually they will serve their time.
Go back to sleep...
You have cited the amendment giving the Fed.gov the AUTHORITY to enact laws to tax their wages. Now, can you show us the actual atatute MAKING them liable for those taxes? The legislation that actually IMPLEMENTS the 16th Amendment? (Like the Volstead Act did for Prohibition?)