Why is public health care such a big issiue in the US?

MONEY. The US has many companies making tons of money and that profit comes from overcharging patients They then bribe congressmen and senators to NOT pass a sensible universal health care law.

the countries that have universal care enforce their immigration laws to keep their health system from being financially overburdened, democrats somehow think we can give everyone everything

In America, all of their problems boil down to campaign finance laws. As long as elected officials are dependent upon corporations to win and retain their spots in government, they'll always be beholden to those companies and help them to spread their propaganda. This is why the US hasn't adopted Universal Healthcare, why children can own guns, why there will never be any change in illegal migration, why prisons are being privatized, why taxes will keep dropping for the rich, and every other bad thing that happens in America. These nonsense issues don't arise in other OECD countries, because other OECD countries don't allow corporations to bribe politicians. It's that simple. But Americans seem rather comfortable with the system, so I don't expect to see anything change.

find one of those European systems that "works"...

...compare the standards they have in place to determine who, exactly, gets to enjoy the benefits of that system... you know, things like immigration...to that of the USA..

...compare the cultural controls they have in place relative to the USA.... you know, things like mandatory national languages, state controls on university access....stuff like that...

notice anything?

There is no such thing as free. How many EU countries are bankrupting themselves by providing "free" medical care? Look it up.

Also, you clearly only listen to the rhetoric of the Left about medical care in the USA. It is foolish to do that.