It's hard to do any sort of study of large groups of people if you can't at some point collect and aggregate data about all the individuals involved.
I disagree. There is no need for information which identifies specific individuals when determining the effectiveness of a drug or medical procedure in a large group of people. There is no need for information which identifies specific individuals for market research or television ratings. Those are just a few examples. Data can be made anonymous without losing its usefulness.
some people don't want health care
I disagree. Some people don't want to pay for health insurance, but when (not if) they break a leg, get pneumonia, or any number of problems which require medical care they want medical care. If they can't pay, someone else has to foot the bill. I call those people freeloaders because they show up expecting health care even if they can't have to pay for it.
Some people also don't want automobile insurance, but I don't see many of them calling it socialist and fighting it at every opportunity.
Never test for an error condition you don't know how to handle. -- Steinbach