The individual mandate type of national healthcare originates in the GOP. The dems wanted a single payer system, like medicare. There are many reasons why the leftwingers are less than thrilled with Obama, including the fact that he didn't try to push a single payer system.
But the smart lefties understand that ObamaCare is doomed to failure and the ultimate result will be single payer. They see it as step towards the ultimate goal, instead of getting what they want all at once.
They play chess, while their opponents play checkers.