"Because Obamacare is NOT nationalized healthcare. It's simply a requirement that each person buy health insurance from one of the same miserable insurance companies that already exist."
It's the same thing, it's just making sure that insurance companies (and their lobbies) buy into it. National healthcare would be the same thing, with the gov cutting out the middle man - something big business wouldn't care for.
We in the UK pay for healthcare too, but we just pay for it through tax and NI contributions. Obama has just done a sleight of hand with how it's paid for, and kept the lobbies on board. The alternative would be a tax increase and a massive reduction in health insurance.