Yes it is a stupid claim. Of course when they buy stuff, just like today, taxes get paid. But the issue is the taxes they are AVOIDING. It is really not that hard to get if you were not blinded by your allegence to this cause. It is just plain intellectual dishonesty at it worse.
But today, they only pay a portion of their tax burden. Remember they don't pay payroll or income tax, just the hidden taxes (and tax costs). Under the nrst, their entire tax burden comes from what they pay on the nrst.
It's just plain you missed that now there are 3 places (at least). Under the nrst, 100% of one's burden is paid at purchases.