Chasing wild geese in search of privacy
Imagine that, every time you bought an item of food, you were expected to peruse the grower's and/or cook's "edibility policy" to determine whether or not it was up to your personal standards of non-poisonousness. (People with allergies do do something like this, and I don't envy them.) Personally, I much prefer the system of regulation by which eaters can trust that all food offered for sale is edible.
I suspect that most of us are hoping that privacy works much the same way when we click through privacy agreements: we presume that any reputable company is only going to use data in ways that we'd expect. Maybe they actually do, most of the time, but no one would ever know because it's buried in legalese.