Why is Obamacare so offensive to some liberals?
Because, as a meme, it was invented to make healthcare reform efforts unpopular with voters by implying that the government, in the form of President Obama, was going to be making your health-care decisions. It's part and parcel with Politifact's Lie of the Year, "the government takeover of healthcare," because it replaces the traditional term for our health sector with the name of the head of the government.
The term also plays into the oft-repeated "liberal overreach" message spread by the president's conservative opponents, who argued early and often that health-care reform was an ego play on the part of a self-obsessed president ignoring the public's wishes, rather than the inheritance of forty years of Democratic campaigning to fix a broken and unjust system. And by merging the terms for health care reform and the President's name, Republicans could attack both at the same time, maximizing their efficiency: Republicans love talking about "job-killing Obamacare" for just that reason.
Joyner mentions that he opposes the law (it "will provide very little in the way of protection and even less to ensure affordability") and, like Appel, just can't understand why "Obamacare" offends liberals, which strikes me as playing dumb -- he's even got a cartoon posted on the page suggesting that the bill is a "government takeover of healthcare," a return to our lie of the year. Another opponent of the law, Meghan McArdle, also doesn't get it. Frankly, it's not hard to understand why many proponents of health-care reform don't like a slur designed to defeat an important accomplishment.
That said, sometimes you have to reclaim a negative term. Like it or not, Obama won't be separated from this law, so liberals have to own this one. I know Matt Yglesias is in favor of calling it the Affordable Care Act, a reference to its full legislative name, and I think that makes sense. But, just as with Fox News' insistence on referring to the public option as "government-run health insurance," the problem is convincing the public that government isn't a bad thing. Luckily, Obama remains the most trusted politician in the country, so this is as good a place as any to start.
Update: Some good reasoning on this question from Ezra.
-- Tim Fernholz