It's really not. If you want medicare for all you have to pay for it.
Bernie's proposal showed where he'd like to pay for it.
It runs counter to current administrations proposal for changes to the tax code. I personally don't like it, but it's still 63% popular. On the bright side most Americans don't think wealthy pay enough taxes. Something I also agree with, but it's not because the rate isn't high enough, but because of the deductions and loopholes.
That aside all I've said is you will need to convince Americans with real numbers why their taxes need to increase, why losing their employer provided insurance is a good thing for those who have it and are satisfied, and more importantly what will the coverage actually look like.
Not everyone is just concerned with having coverage. They need to have adequate and affordable coverage.
My view is the proposal is a good jumping off point to move the conversation. But those things you say are disingenuous questions, it doesn't matter if they are to be honest, have to be addressed because that's how these things go in our political landscape.
These aren't wholly my positions, but they are the types of responses you'll see.