Everything you need to know about why the right-wing is going after unions can be learned by simply viewing two of the slides from this study by the Center for Responsive Politics:
It’s not about saving money. It’s not about giving those who govern more control over feisty unions. It’s not about free markets or any of that other bullshit. It’s about destroying the opposition, drying up liberal funding, so that they can give more tax cuts to the Koch brothers.
They want all the money. Period.