When you say slavery, what would they make the people DO? Work harder? Wouldn't they have to market it as some kind of utopia first?
Taxation is slavery.
Then why does the English language have 2 different words for it?
Incidentally, Orwell covered this extensively in his clever satire, 1984, where the dictatorship was trying to purge all unnecessary words from the English language. Nuance? Devil in the details? Fuck that shit, it's all black OR white.