The critics say that the rich already pay 35% of all tax revenue...what incentive is there to even get wealthy if you have to hand half of it back?
We have marginal tax rates, Phat. There's no system of marginal tax rates where earning more money pre-taxes doesn't result in you having more money post-taxes, as well, unless you're talking about tax rates at 100% or higher. Even at a top tax rate of 99%, getting richer pre-tax still means you take home more money post-taxes.
It's true that the top Federal tax margin is 35% or so. But it's a marginal rate - and the margin starts at $500,000. That means you only pay a rate of 35% on income in excess of $500,000.
Because of the diminishing marginal utility of money, people don't benefit as much from earning a two-millionth dollar as they do from earning a thirty-thousandth dollar. Therefore it makes great practical sense to transfer some amount of wealth from the rich - who lose little from having that wealth confiscated - and giving it to the poor, who benefit greatly from it. It's not unfair in the least to have a progressive system of taxation with high rates for the top margins, and it doesn't in any way remove the incentives to make more money (if that's what you want to do.)