I was a US employer during the post dot-com boom recession in Silicon Valley. I witnessed first hand that the tying of health insurance to having a job puts urgency into job-seeking in the US that just doesn't exist in most of Europe. Prospective employees pursue you with an energy unthinkable here, and an important part of negotiations are the question of health insurance. Many Americans think this is basically a good thing – it reinforces the work ethic and builds moral character.
I think that this is essential to the view of normally conservative Americans – the way the US organises health care insurance is an important part of the moral fabric of society. And, like it or not, it is and important determinant of attitudes to work. Insurance is intrinsically something which undermines individual responsibility, whether it is social or private insurance. But the threat that if you're a bad worker insurance might be taken away is a strong discipline.
A post on Derek Bownds' wonderful Mindblog leads me to the thought that opposition to non-work related health insurance has deep ties to the religious conservatism of much of America. The claim is that some traditional hunter gatherers and many modern Europeans are not religious because they feel secure here and now. The implication is that to rediscover religion, Europeans would need to become socially insecure. The corollary - not in Bownds' post - is that opposition to healthcare reform in the USA is not only, or even mainly about economics, but rather about maintaining a moral and religious fabric to American society. The argument, in other words, is not really about the technicalities of the public option – it goes deeper into America's polarised state.
Here is a passage that Bownds quotes (the original article is unfortunately behind a paywall)
Breaking the insecurity of health insurance tied to work, whatever the economic and social sense of the proposal, will do no good to church attendance.