A monster? No. But I do think refusing to pay into a system which will save others lives (and from which you'll likely benefit yourself) seems a tad selfish to me. But the problem lies in the difference of opinion over whether health care is a right. I will always believe that it is.
The people who suffer under a pay-for-care system are mostly people who've been unfortunate enough to be born into low income families... who've gone on to have little education and work very hard most of their lives in low paid jobs (earning just too much to qualify for medicaid). I cannot see how it can be justified that those patients be denied life saving treatment (e.g. cancer treatment) just because they've been unlucky in life.
Yes, health care is a service, and yes it should be paid for. I don't think it should be paid for (and it is paid for, by taxes). I do not believe it should be refused to those who just cannot pay. I do not think you should be required to use your own life savings to pay for your cancer treatment. It is absolutely insane and cruel to me to imagine my caring for someone in ICU for months and then handing a bill to them when they get better for thousands of pounds, to pay me for it (worse still, they die and the bill gets handed to their grieving family!). I do not do my job because of the money. I do it because I want to help people. I'm not sure the same can be said of all American doctors. The biggest supporters of the NHS in the UK are the doctors and nurses who work within it. I'd probably earn far more money working in the US, but I would feel absolutely terrible then billing my patient for the treatment I've just given them.
Yes, the system is open to abuse. Any system is. Your current system is already being abused! I really think the illegal immigrant argument is being blown out of all proportion. As you say, illegal immigranta can already access emergency medical care. It is unlikely that a public health care system would change that (and in my opinion it shouldn't). But a public health care system would still NOT provide free long term treatment to illegal immigrants. Yes, it would still be abused by illegals, but the abuse is unlikely to be worse than it is now.
And I STILL don't see how concerns over abuse by illegal illigrants is good enough justification for punishing hardworking Americans, who have worked (and paid taxes) all their lives, in minimum wage jobs, but cannot afford treatments which could save their lives. Why punish the majority to hit the minority (the illegals)?? And ultimately the punishment is death or disability, so it's not one to be taken lightly.
I need to go to work, so will reply to the rest of your comment later (but none of the issues you've mentioned are an problem under the UK system).