Path is young (and building a service, not a device/OS) and it can be abandoned for something similar since all they're keeping is data. Once you buy a gadget, that's an investment on your part which will make a lot of people hesitant to give it up and the culture it that surrounds it.
And I wouldn't bet that Apple will be able to survive scandal after scandal and still survive unscathed. Cook is no Jobs.
If a developer refused to implement a feature due to their ethics then the company would do the following:
* Move engineer to different project
* Set unrealistic goals/deadlines/expectations
* After engineer fails, voice concern about performance
* Set up performance review and improvement plan
* After causing engineer to fail a second time due to unrealistic expectations, fire them due to poor performance
Even if that engineer writes a blog post, enough has happened between his initial refusal and termination as to make conclusive proof impossible. The discussion will be a he-said-she-said affair as his former employer makes a counter-blog post explaining the engineer's poor performance.
A lawsuit is similarly out of the question as most companies have sufficient funds to cause delays in court, thereby causing you to spend all your money on attorney fees and bleeding you dry.
It's not like hospitals haven't contended with this exact thing for a very long time. The wills of surgeons/doctors and their hospital administrators do not always match up.