Just because a government program benefits a lot of people (in a country of 350 million, including illegals), doesn't mean that it is a "good" program, or that it is a Constitutional program, or that the taxpayers can afford it without borrowing trillions from the Chinese.
Consider the $5,000 Visa cards that are reportedly being handed to the hordes of illegals who are being welcomed at our southern border. Those cards help A LOT OF PEOPLE, don't they? Those people would be much worse off without the cards, wouldn't they? But where does Congress get the power to give taxpayer funds to criminals (jumping our border is a crime)? Nowhere.
ACA is an unconstitutional law that was sold to the American people on a pack of lies. Furthermore, it stands historical principles of INSURANCE on their figurative heads. Rather than having insurers take clients at random with some reasonable preconditions (insurance is a BUSINESS, after all), ACA says that insurers MUST take clients whom it knows are awful risks - they will be claiming mountainous medical costs for as long as they live. And because the insurance companies are compelled by law to take these "high risk" clients, EVERYBODY ELSE MUST PAY MORE FOR THEIR HEALTH INSURANCE. "We" did not save $2,500 a year on health insurance premiums every year, did we? In fact, we are paying more than ever (although for most people, their employers are paying the higher premiums our of their earnings).
But ACA has put congressional Republicans in an untenable position. They don't want to craft a "replacement" for O'Bamacare, because the replacement would also necessarily be unconstitutional and just as bad fiscally. The American people WANT the insurance companies to be forced to accept high-risk patients, and they WANT to have no lifetime caps on coverage. So when Republicans are forced to talk about their coming replacement for ACA, all they can say is, "Whatever we do, people with pre-existing conditions will be protected, and there will be no lifetime caps."
Trump is a populist, and has no interest in articulating this conundrum or how it will be resolved. He knows that his primary constituents want to hear that ACA will be repealed, so that's what he says. And of course, that's what the stupid linked article latches onto. They won't be troubled to report the aforementioned Republican promise.
File this along with all of the phony headlines about Republicans cutting Social Security and Medicare. They are all bullshit, but people are stupid enough to believe it.