Health care is what your doctor does; Health insurance is an administrative function by which your doctor is reimbursed for the treatment they provide you, after they provide it. All Medicare-for-All does is consolidate that administration under one entity that has the added benefit of using its leverage to negotiate for cheaper fees and costs.
Medicare-for-All doesn't eliminate health care; it eliminates provider networks, so you can go see whatever doctor you want, not just those limited to within your provider network because of your insurance company.
Medicare-for-All doesn't eliminate health care; it eliminates private insurance companies that don't serve a role in your health care presently, and never will. No health insurance company takes your temperature, checks your prostate, does a mammogram. No health insurance company removes an appendix, prescribes a drug, or does a blood test. All a health insurance company does is reimburse providers for all those services, while keeping as much as 20% of every dollar you pay in premiums for themselves.
The choice that the Republicans on stage last night were talking about wasn't the choice of doctor, it was the choice of administrator. Single payer provides true choice and freedom; choice of what doctor you want to go to, and freedom from provider networks and drug companies.
You don't have freedom or choice in our current system. You cannot go to whatever doctor you want and not pay exorbitant out-of-network fees in our current system. You might think your current doctor is great, but because private insurance stifles choice and freedom, you don't have the freedom to explore other provider options to compare services. Think of it this way; when you shop for a car, you wouldn't go to just one dealership would you? So why would you not want the freedom of choice to explore different health care options, to compare and contrast with what you currently have? Wouldn't that be taking personal responsibility for your health?