Income taxation is piecemeal slavery and progressive taxation is totalitarian psychological slavery.
Easy to see thaumaturgically:
Better wages => higher status + more slavery.
More slavery becomes linked to higher status.
Population tries to elaberately mimic the habits of slavery in an attempt to gain status.
Result: slave population.
Gee, where do we see an essentially slavish population?
Refresher: the core slave mindset is external motivation. The slave doesn't do anything unless massa tells them to do it. Or they're starving to death; such impulses look the same as massa whipping them.
Problem: slave habits are inherently, biologically linked to low status. The population becomes convinced that no matter how successful they are, they're scum. They feel like the sovereign (highest status) is telling them to be scum, and as slaves, they obey.
Being scum, they cannot possibly fight back, which justifies the slave habits.
An absolutely brutal trap.
You have to get fancy to unpack the thaumaturgy into psychological atoms, but it does work. The populace has to understand in their bones that income taxes are isomorphic to piecemeal slavery, but they in fact do understand that.
Income taxes make it slavery at one remove, because you decide which job you work instead of massa deciding. This decouples the knee-jerk [feels like slavery] sensation. This helps hide the slavery from the executive consciousness. A big win for narcissism. However, the rear parts of the brain will notice if they spend even a second thinking about it, and do. Taxation is theft. Slavery is nothing more than direct theft of labour, QED.
Bonus round: because the slavery is partial, it's possible for the executive consciousness to focus on the non-slavery bits. If you had to work on a plantation under the whip for two days of the week, there would be no hiding it. That's not the implementation, so it doesn't feel the same, but taxes are perfectly isomorphic to stealing your work this way, so I don't see them as any different.
By contrast, poll taxes and rents can, in principle, possibly be fees for service.