Think of it like going to a concert where they pat you down before you go in and they use that consent to be searched to go check your car, your house, your work, people you know, where you spend your money, where you eat, what your political alignments are, etc... YEP, you sort of gave this info to them voluntarily too.
While I think many have said this many times over including me, this has been going on since they've been around, it is really just that people are now realizing to what extent and how invasive it can be.