Well, with the Income Tax, you can choose whether to work or not. I'd say they are about equal in "voluntariness". C'mon. Are you kidding?
Right now, if you work for someone else taxes are withheld immediately from your check. Under the FairTax, when you decide to spend your money, you will then be taxed. To a large degree you decide your tax bill and when it's paid, not the feds.
To imply that FairTax supporters are saying otherwise is less than honest and you know it. The Feds talk about a voluntary system, but neglect to follow that up with the consequences that you'll face for not volunteering.
Well this isn't a very profound point, but here goes. The income tax is taken before you get a paycheck, true, but the sales tax is taken before you get the purchased item. You can buy or not buy, true, but you can also work on the books, or not. Many folks get their money without paying the income tax man -- either they don't work (e.g., live on investment income or welfare) or get paid under the table (e.g., illegal aliens or waiters) so there is a choice. Much of the 'choice' with the sales tax is similarly phony -- you are not going to walk to work instead of drive, etc.
Your statement regarding an implication I made is way off base. I implied nothing. I don't have a dog in this fight -- just an interest in truth.