I don't know why Uber is complaining. All they need to do, after all, is to recruit drivers with a commercial license; require the vehicles to comply to commercial safety standards; and provide the needed insurance. It's not as if the deck is stacked against them - the other services they compete against all follow the same rules.
For my part as a potential user, liability is the real issue. I would never risk taking a car service where I'm not fully covered in the case of an accident. It's not just medical and other costs for myself; if the driver is not licensed you, as the one paying for the ride, may be regarded as co-responsible if your driver caused the accident in the first place. You want to risk hundreds of thousands of Euro in damages to save a few bucks on a taxi ride?