I understand you feel strongly about this, but the notion that they're accomplices to murder is groundless at law and in ethics. To be accomplices it has to be established that they had criminal intent. They patently did not. Providing some sort of means or assistance to a criminal without mens rea does not mean being an accomplice ~ for example, were a criminal to take an Uber to her victim's location one can't just aver that Uber are an accomplice. It's a very different matter if the criminal were to disclose that she was about to commit a serious crime.
I think you're ignoring criminal negligence in favour of criminal intent. Those responsible for this data cannot possibly not have understood the ramifications of someone with nefarious intent accessing it. That's the fundamental difference. Your analogy is a little flawed. A similar example would be someone who is authorised by Uber accessing their GPS data to ascertain the location of their ex-gf and going and murdering her. Of course Uber in this scenario would be vicariously liable through criminal negligence however in the case of the mobile companies to a lesser extent as those they entrusted with the data acted negligently.
It all boils down to whether mobile companies can argue that a piece of paper saying you should do 'x' and shouldn't do 'y' is sufficient argument in such a scenario and absolves them from liability.