It strikes me, when you mention discriminatory practices, that it's a very compelling example. Obviously discriminatory practices, regardless of age, should be outlawed—full stop. But the use of data itself for reasonable business practices doesn't strike me as a particular problem. I recognize that I may not understand the algorithm behind it, but I do understand what it means to use my preferences to advertise to me based on those preferences.
I worry that when we talk about not understanding the algorithm, then we undo the ability of businesses to advertise or to use the data in a meaningful way that a lot of consumers would appreciate.