What everyone missed
From the UK NHS site:
As a UK national, you can receive free or reduced cost emergency healthcare in any European country that is signed up to be part of the European Economic Area (EEA), as long as you have a European Health Insurance Card (EHIC). This replaces the old E111 form from September 2005 and is available online (see Selected links), by phoning 0845 606 2030 or from post offices. Each member of your family must have a separate EHIC.
You are eligible for an EHIC if:
--you are a UK national and resident in the UK,
--you are a national of any European Union country that is part of the European Economic Area,
--you are a stateless person or a refugee,
--you are a widow receiving a UK state pension or Widows benefit, whose late husband was a national of a European Union country and living in the UK at the time of his death, or
--you are a widow or widower receiving a UK state bereavement benefit, whose late spouse was a national of a European Union country and living in the UK at the time of his or her death.
There are some countries outside the EEA (such as Australia and New Zealand) that have reciprocal agreements with the UK. This means that UK residents can receive free or reduced cost emergency medical treatment while travelling in these countries. You will need to provide proof, such as a British passport or photo card driving licence, that you are a UK resident in order to receive treatment.
If you are travelling in a country that does not have healthcare agreements with the UK, you will need to take out medical insurance to guarantee that you will receive treatment if you become ill. Your travel agent can advise you of the type and level of cover you need for your journey.
In other words, these visitors did not take the preparations they should have, and that were recommended by their own health care, and are blaming the U.S. system for their own oversight.
I bought extra insurance before I went to Europe, and it's a good thing I did.