South Korea could mass test because of how small it is, and because it has one of the best hospital and healthcare systems in the world. They are also a highly compact nation where testing labs are not very far from anywhere in the country; that is not the case in the US.
We do not have the time, resources, or public trust to waste on sampling/testing measures that are not fully vetted yet.
Delays cost lives yes, but how many more lives will be lost if tests aren't accurate and the public loses trust in the entire testing system?
I get wanting to do something, or have something, NOW. But rushing this sort of thing is likely to make the problems we face WORSE, not better, in the long run.
If it's shipped with a big label saying experimental, I don't think it will be a problem. It's not like the test hasn't been tested, but just privately, not by the FDA. The FDA also is known for putting delays in place constantly, trying to ensure perfection instead of good enough. This means that we avoid side effects, but it ignores the unseen costs. Overall, I have confidence in the public that a non-verified test which allows for information is a good thing, not a bad thing.
And we definitely have the resources. The tests already exist, and are being made by a private company. I'm not seeing how this costs people resources. And spending time and resources to expand the ability of the US to give COVID-19 tests is exactly how we should be doing it.
Why are these people so incompetent , it like they're trying to deliberately sabotage this country
It's not incompetence, it's skewed priorities. A FDA regulator approving something that doesn't work looks bad, but just delaying until they are certain doesn't harm them at all. Although the delay does harm the public, it's not as obvious. For more on this, look up public choice economics.
There's also an element of regulators seeing regulation for regulation's sake as a good in and of itself, and on top of this big companies love, LOVE, regulation, as they have the legal might to deal with it and put in place regulators to write it, while small companies are driven out of business by it.