I believe the concern about uninsured is not the numbers but who'd be affected. Office workers, which can quarantine rather easily, are likely to be insured. But those in contact with most people on a daily basis (e.g. fast food workers, retail employees) are more likely to be uninsured and also have a lower allowance for sick days or PTO.

My concern would therefore be that the people that cannot afford health care or quarantine are also the ones most likely to act as multiplier as they come in contact with hundreds of people a day. That's not a purely US problem, e.g. delivery drivers or Uber drivers also tend to be low wage and self employed in Europe.

But in the US the combination with the lack of health insurance could make this worse.