True, the Fair Tax is actually a sales tax but to the extent you have to have either wealth or income to buy things, it turns out to be a tax on both income AND wealth. True, everyone gets the same prebate, but what if someone’s income is less than the prebate? That’s where the worms come in.
I see your point and feel in no way contentious toward it.
However, I see a relatively few (fewer than today) folks paying a negative tax as a “more sufferable evil” than having politicians in Washington DC using the tax code to manipulate behavior, punish their enemies and reward their friends.