Just in case anyone missed your math, when a FairTaxer is talking about a 50% FairTax (inclusive), that is actually a 100% sales tax as most people think of sales taxes (eg. double the shelf price to get the final price)
Since the tax is only 50% of the final price, it is a 50% FairTax-- got it?
Your emotional hatred of tax reform betrays you.
Your statement would be correct like this:
Since the tax is only 50% of the final price, it is a 50% tax inlcusive rate-- got it?
That being said, people use both inclusive and exclusive rates for different reasons as you note. Most people use inclusive for income tax and payroll tax. Most people use exclusive for state and local sales tax.
Which method to use for a sales tax (usually exclusive) that replaces the income and payroll taxes (both usually inclusive)?
I use both. One to determine after tax price and one to compare to income/payroll tax. However, you are free to use whichever you prefer. They are both equivalent amounts of tax after all.