That's one point of view....set in the context of the times, the clause in the Illinois constitution made sense then because the state income tax was relatively new and a proposed increase in the income tax rate so soon after starting it in the first place generated a lot of debate.
The idea apparently was that if you make graduated rates unconstitutional, then the state would need to keep income tax rates low since everyone would be affected; and people had only grudgingly come to accept any state income tax at all in the first place.
At that time, most people viewed budgeting as: you start with the revenue you have and then figure out how to allocate it among competing priorities; it was not a popular view then that you make promises left and right to get elected, and then try to figure out where to find the money to pay for them.
I recall Richard M. Daley opposing a small social welfare program. He said, paraphrase, once you try to do something nice on a temporary basis to help out a few people in need, then pretty soon it gets viewed as a 'right' and everyone starts clamoring for it, and that blows your budget all to h^ll.
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