“The first tax code was a ‘Flat Tax’; 7% for the wealthiest 2% and 1% for everyone else.”
That is a progressive tax.
You missed the point. You can make X% and only X% and call it flat.
The point you missed is that you can’t keep it ‘flat’, any more than previous generations of Americans kept their 2 ‘flat’ brackets from growing into many more brackets of flatness.
So go on and argue about semantics. The point is you and flat tax lovers have no way of stopping a flat tax from growing into ever more brackets and becoming progressive. You can’t do it because of the 16th.