It's reckless for progressives to dismiss concerns over funding single payer as 'trolling'...

[frazzled]

5. We do understand how Medicare works

Maybe you don't understand the difference between Medicare and Medicare for All so well.

Currently, everybody who works pays into Medicare their entire working life. Current workers pay for the healthcare of older Americans who qualify for Medicare insurance (those over 65). (When these workers become eligible for Medicare later in life, it will be the younger workers who are paying into the system to pay for their care.) To extend the Medicare program to all, there would have to be a lot more money in the system ... a whole lot of lot more, since the amounts being paid in now cover only a segment of the population (about 12.5% of the population, and that's the highest level ever, due to the baby boomers). That's fine, but where that money comes from to fund care for 100% of the population is open to a lot of discussion, and probably a lot of controversy.

A bill that sets out Medicare for all but does not include the specific ways in which the costs will be paid for (as the ACA did) is not a bill at all; it's an aspiration. Passing it would not enact the program, because the funding would have to be passed separately, by tax increases or any of the other means suggested in the white paper. And you know how that goes. There can be no Medicare for all without the agreed-upon and sustainable funding. (It's like Trump promising his supporters that he will build a wall, but there is no agreement--and probably never will be--on how to pay for it.) So yes, it's a concern. But not at all a false concern.