Please cite your evidence which supports your assertion that most GOP voters are for a graduated income tax.
I agree with your sentiment, however, most people likely DO support it, because...they are ignorant of it, and don’t understand the unfair, destructive, and corrosive nature of a graduated income tax.
I would not be surprised if most voters “favored” it. They likely have no idea what it really means if they think about it.
I bet that if you sat them down, and explained it, personally and face to face, most would be against it.