The ACA Is far from perfect but it was a significant step up from what we had before, and the party that spends all of their time trashing it has never made any sort of serious attempt at creating any sort of alternative.
The amount of people that actually want the government to have no role in providing health insurance or health care in this country is vanishingly small.
Ultimately the health and life of the citizens is one of the most foundational concerns of any nation. You literally can't just ignore it. You have to face it, whether you want to or not.
Meanwhile, the ACA was quite frankly a love letter to conservatives.
It kept the US profit-driven system on life support, and it's a form of the same system proposed by Nixon, and again by republicans during the Clinton administration's push for healthcare reform, and the system enacted by Mitt Romney in Massachusetts.
The only reason republicans opposed it on party lines during the Obama administration was politics: they were forced to denounce the system they loved due to their status as the opposition party. In another universe they would've celebrated their president signing it into law.
Actual leftists are probably fine with ending the current system because it will bring so much pain to the voting public that it might actually get them off their asses to bring in single payer. As the saying goes: "You can always count on Americans to do the right thing, after they have tried everything else."
revisionist in the extreme. Not reading the rest of your comment after this one.