You can not improve an economy by sucking even more resources out of the productive sector for the politicians to lavish on their cronies.
Actually, you can. Because surprise, surprise, the "politicians" give it to their "cronies" who give it back to the "productive sector". Spending the money three times increases the total of economic activity more than spending it once. It is pretty crazy, especially if you're a libertarian who believes the government is an evil black hole where money goes to die. The biggest problem for economy isn't who takes or gives the money, it's who holds on to it. If it's not moving, it doesn't get counted.
Furthermore, higher taxes can actually subsidize employment. It's counter-intuitive, I know, but for corporations employees are an expense that reduces profit. Since taxes are only applied to profit, hiring more employees is effectively cheaper for the owners when taxes are high (if they would lose 30% of the profit to taxes, they're only effectively paying 70% of the price of an additional employee out of the profit they would keep, if it were 50%, they'd only be effectively paying half the cost for another employee*). Since capital gains are taxed at a lower rate, when taxes are higher it can be more effective to invest profits into growing the business.
* numbers for example purposes only, I'm not avocating for any particular tax rate here.