Exactly. That's why the tax should not be fixed percentage, but should have the "starting point" under which you don't tax somebody at all, and it should have "

Exactly. That's why the tax should not be fixed percentage, but should have the "starting point" under which you don't tax somebody at all, and it should have "protect the poorest taxpayers" area which also can be different from the "it's effectively equal" area. But somehow in the US people are trained not to think in that direction. It's more common to be aware of such possibilities in Europe, or to expect from the system not to completely ruin the life of the poorest.