Simple answer: Because they can, because it's lucrative, and because it's not as obvious as raising taxes. Imagine you could legally print money, and when anyones asks about it, you can just dismiss it with: "I'm stimulating the economy"
Simple answer: Because they can, because it's lucrative, and because it's not as obvious as raising taxes. Imagine you could legally print money, and when anyones asks about it, you can just dismiss it with: "I'm stimulating the economy"