So lets clarify: in social democracy one trades the basic fundamental right to freedom of the fruits of ones labor in exchange for public "rights" like education and health care. More importantly one trades one's neighbor's fundamental rights and will use force to make sure that he complies. To continue the analogy that is on some levels literally true one is making his neighbor a slave.
Personally, I think if one wants to trade the fruits of ones labor (time and money) for payment of health care one should buy insurance. If one wants someone else to get said healthcare then one should pay for it himself. But we must draw the line at deciding that someone else should pay for another persons healthcare. As you said that is immoral. Again, as you said; there is no defined end to how much will be taken from some and how much will be given to others.
Right, sure, and when an individual who has made the choice to go without health insurance has a major illness or accident, the provider will gladly take care of him, give him the rehab and physical therapy he needs to get back on his feet and once again become a contributing (voluntarily contributing, of course) member of society as private charity will be happy to pony up the quarter million or so that his care costs. There will be no need to give the patient the minimum care necessary to get him out of the door, then pass the cost on to other patients.
Which makes me wonder just why anyone would bother to have private insurance anyway, as it would be unnecessary.
Here in the real world, however, where unicorns do not frolic and where people act on their own self interests most of the time, such a system just might not work as planned.