Emergency rooms do not provide medical care. They provide emergency care, and they do charge people for it. Lack of access to health insurance does mean lack of access to health care for people who can't afford to pay. Hospitals may be required to treat people, but they are not required to do it for free.

If I could afford to pay the emergency room to provide my medical care (a lot more expensively than a regular doctor's office), then I could afford to see a regular doctor. I cannot afford to do either. If I showed up at a hospital emergency room and requested treatement, they would be required to give me whatever treatment would stabilize me, then they would sent me home (without necessarily correcting the problem) and then they would send me a bill.