Why do liberals believe Obamacare was a great accomplishment?

Yup

Because they’re delusional. Liberalism is a mental disorder.

It could only be an accomplishment if was called Obungacare.

Ignorance.

No, you weren't always free to purchase health insurance. Many could not buy it, at any price. And even those who could buy it sometimes had to pay over $2000 a month for it. It costs much less than that now.

I am pretty much a liberal as you may describe it since I never vote Republican, but I do not think the Affordable Care Act was a great accomplishment. As you recall when it was being constructed, the establishment Democrats and Obama refused to listen to a lot of better suggestions....and only preferred to listen to the proposals by the insurance companies. People who wanted Medicare for all or the so called public option that would be similar to what most major democracies in the world like Canada, France, Great Britain, Germany, Australia etc have were shut out of the hearings process.....in other words the entire thing was rigged by the establishment so that the much more popular option that would have made health care insurance costs way more affordable to American were not discussed at all. So, what I just stated above is a fact. I know your question is intended to play into the whole partisan liberals are no good thing or libs are stupid etc... but if you are honest, then my answer will prove to you that its not that libs think it was a great accomplishment, its just that Obamacare was an improvement to the lives of millions of mostly lower income Americans to make health care more available and affordable for them. Liberals care about such things, so I guess this is why they like Obamacare because its better than just saying ho hum who cares if Americans are dying and who cares how high insurance costs for the average citizen, I don't care, as long as I got mine, I am just fine...as taking care of me me me is all that matters attitude of Republicans. In short ObamaCare had problems but it was a start in the right direction. To me its because flaw even though it did some good was the forcing of citizens to buy insurance who did not qualify for a subsidy while really doing nothing to drive down the costs for them. Its like oh you poor people, you now have way affordable insurance, but you middle class people who are not necessarily rich you have to buy that expensive insurance and if you don't we will fine you. So, once again, I am a liberal, and have just proven that the assertion of your question, like most things right wingers spew is a falsehood.

It legalized white-collar crime in the healthcare industry

It costs me a lot less now.

I wouldn't call it a great accomplishment, since it was more of a compromise with Republicans. A great accomplishment would have been taxpayer funded single payer.

It dramatically expanded insurance coverage. This is true both in terms of who is covered and also in the quality of the insurance. It forbid, for example, denying people coverage based on pre existing conditons. It also mandated that all insurance cover certain things, including maternity care, mental health care, etc. It expanded Medicaid to cover millions more people (and would have done more if Republicans hadn't voted to screw their own citizens out of political pique). The law also requires insurance companies to spend a certain amount on patient care. It also offers financial help to people purchasing insurance on the open market. Finally, it slowed the growth of medical spending slightly.