Agree, but the thesis of this point is valid. To show how hard it is to actually finance this stuff,
look at Bernie's white paper on paying for MFA. Just to give a reference, total income tax revenue is ~$1.7 trillion and the top 20% pay ~87% of those taxes.
Now, of the $3.2 Trillion per year costs of MFA, roughly $2 trillion is already publicly financed (Medicare, Medicaid, etc). SO that leaves $1.2 trillion in additional revenue. So you'd have to roughly double the income taxes of the top 20% to make up that difference if you didn't raise taxes on anyone else. I think that's a fairer way to describe Crazy's point.
So we need at least $12 Trillion over 10 years. This is NOT easy to come up with.
Bernie calls for a 4% employee and 7% employer FICA style tax. According to him, that raises a total of about $8 trillion over 10 years. So we still need $4 trillion. His wealth tax on the top 0.1% only brings in $1.3 trillion over 10 years as an example. He's got a variety of things he proposes as options to make up the difference, but you get the idea. It's really hard to figure how a fair and equitable way to fund something this significant.
The better way to win this argument isn't to justify how you pay for the MFA costs, it's to argue that MFA will be net cheaper over 10 years than continuing with private health insurance, while insuring more people, and we have to figure out how to pay for it anyway