I might be able to help answer that with a true anecdote. I have a couple friends who would pay no income tax. They don't like to see their PFD drop but still prefer that over an income tax, even if they are currently unaffected. So why in the world wouldn't they support a tax that only affects the "other guy"? They give primarily two reasons, which may be applicable to the majority of Micciche's constituents:

1) They strongly suspect government will grow under an income tax. Government will raise rates and expand the brackets, eventually coming for their earnings too. And given the government's track record they are probably right.

2) They hope to grow their earnings over time and don't want their hard earned money being taken when they do, especially with the inevitable rate-hikes that would come down the road.