The thing isn't just that Uber may break the law, but that it encourages others to break the law. Call it anti-libertarian, but in Germany a company shares responsibility for the behaviour it is creating. They would have to put controls in place (within reason) to ensure that Uber drivers don't break the law -- but of course they don't because they're well-aware that that would reduce the number of drivers and drive up costs and prices.

Basically, Uber is breaking the law when it comes to passenger transportation the same way Mega was breaking the law when it came to file sharing. It created an environment that promoted illegal activities.