Can you tell me what it is about universal health care that makes everyone terrified?

Help me understand what it is about socialized medicine that makes people tremble in their boots. They have it in the military and prisons. Most of those soldiers and inmates don't have the money to pay for their own health insurance, so someone has to look after them. I'm surprised Michael Moore didn't include that in his movie Sicko save for the detainees in Guantanamo. I thought doctors go into their profession to help people not because they want to drive 5 BMW's, own McMansions with 18 widescreen plasma TV's, and go play golf with the CEO's of the pharmaceutical, and insurance companies every Wednesday afternoon. Can someone explain to me why it's such an atrocity that 50 million Americans should be given access to health care when they can't afford insurance while the rates and costs are going up exponentially? Tell me another solution you can comprise for I'm all ears.