1) You see sales tax every single time you buy something. That's daily, weekly, etc. Income tax isn't quite as obvious for the majority of the population since most of it is automatically deducted from the paycheck and you never actually have that money. That is a huge, huge, huge perception problem it has to address.
2) If it happened, the most likely course of action would be massive non-profit organizations emerging to do things like distribute food and goods. Because they don't pay sales tax. And the wealthy left will do everything in their power to circumvent the system for the poor. So you'd end up with these massive tax shelters that are completely legal because they exist as a non-profit.
Its just incredibly unrealistic. So far out there, that he deserves derisive commentary from the press.