Public servants are directly paid from income tax of the US populace. Therefore, income tax deductions for public servants should be disallowed, as they represent a 2X deduction on the same (already taxed) income.
The end result of a public servant taking a deduction reduces the public payer contribution of tax to support the infrastructure of the United States of America when that same public servant is tasked with maintaining it.
Its a reduction of profit to the US govt collective income.
A possible later interpretation might conclude that govt employees should not be taxed at all since their income is derived from taxation.
This is feasible but if enacted should result in a lowering of govt employee wages to match net revenue minus incumbent taxes.