So you would support mandatory enrollment for all US citizens?
All seniors are enrolled in Medicare. Is that the same as mandatory enrollment? Seniors are also free to get their own insurance, or even pay for their health care out of their own pocket. Single payer would be pretty much the same.
Single payer would be paid for by some tax, which may be progressive or not. everyone would be covered, the overall cost of health care would go down, and we'd save trillions in the long term.
you are already paying for other peoples health care: through county taxes to pay for emergency rooms used for the wrong things, and inflated hospital bills to pay for those without insurance. why not just do it efficiently?