Easy answer, the American tax payer is not the world free medical provider.
You deport them!
You can deport them, but they will likely come back. If they come back and develope the disease, they will infect many others. They will not seek treatment, because they do not want to be deported again.
No, the US is not the world medical provider, but if we do not treat those who are here, they will make the rest of us sick.
Deporting them would be an answer if the borders were secure, but they aren’t. Deporting them now, without medical treatment, will put many American citizens at risk. Same thing with the criminals. We can deport them, and they will come back and commit the same crimes again, or we can pay to lock them up, so that we are protected.
It all comes down to controlling our borders.