But almost all location data is "public". I could follow you around, staying in public places, maybe have a friend or two help me out. And hire an army of priva

But almost all location data is "public". I could follow you around, staying in public places, maybe have a friend or two help me out. And hire an army of private investigators to do the same for a bunch more people. But that doesn't scale, so much so that the difference in degree becomes a practical difference in kind. That's just an exaggerated version of the difference here. One of the most effective practical tools to combat bulk surveillance is to increase the cost. I'm also of the opinion that people are kinda asking for this by giving that data away and posting it publicly, but that doesn't mean those already collecting this data have no responsibility if they package it up and make it easy to use for surveillance.