This is not about price fixing. Uber can (and in UberBlack does) legally operate a car-for-hire operation that is cheaper than cabs. This is about not complying with safety and other operating regulations, which makes it easy for UberPop to significantly undercut the competitions prices. So the competition sued for unfair business practices (since complying with safety regulation costs them money) and the case is so clear that the court granted without any oral arguments a preliminary, enforceable injunction.