Have you ever entered your phone number or member number at a business for a discount? You think they aren't tracking that? What about just tracking you by some hash of you CC info?
I'm sure there were 19th century New York shopkeepers that noticed a particular influx of specific immigrant nationalities in their shops, and may have inquired further and tailored their goods slightly.
Every good business owner has used info about their customers to improve their business. It's impossible to have a transaction without leaving some information.
This, like most "new" things enabled by technology, is a matter of scale. We need considered and appropriate limitations to protect us, not knee-jerk reactions that actually cause harm because we haven't considered everything.
Personal liberty is important, but it doesn't trump all considerations. If we can actually utilize the information to help research new treatments and further our knowledge of the human body, allowing the collection, and careful protection and anonymozation of the data is for the greater good, and worth the risk Imo.
This is a good thing to legislate though.