I take it that they mean that it is indirectly a tax on the employee in the sense that it is money the employee could have earned but does not because the company has to pay the tax. Could have earned as in the salary could have been higher without it.
On the otherhand, that is true for any tax a company has to pay, just not as directly releated.
(Or I could be wrong and they mean something else.)
But would not that depend on how OP's time is valued in this case? OP could argue that their expertise costs $14000/hour ($70000 over 5 hours). I am sure that they would argue the hour cost, I have not clue how the IRS handles something like this.