First off, IT IS NOT FREE!!!!
Taxpayer funded maybe. Somebody pays for it.
Second, our government is too incompetent to administer it. I had med-cal once. My son needed his vacines (you know, those routine shots that take less than 15 min). I made his appointment. I had to go to county because med-cal had changed me from my chosen doctor (who accepted med-cal). I made his appointment and showed up early. Three hours after the appointment time. I asked the receptionist how much longer it would be, because it was way past my appointment time. "I don't know, Everyone's appointment is at the same time."
I had other errands I had to run that day because I actually work, so I only had two days to do stuff. My son did not get vaccinated until few months later when I got healthcare through my work. If I was still on med-cal, it would be effectively the same as no healthcare.