If they immigrated to the US legally, then they have every right to live in the US and (if they're fully licensed) practice medicine in the USIn all seriousness, I think his point is that they should all be deported so that real murican doctors can extract the monopoly rents that would make being a doctor worth it again.
I'm of the view that the US (and a lot of other countries) should be training more physicians. Not just a few more, lots more. If there were a surplus, then competition would drive down the price of seeing a doctor.
If there were a perceived shortage of say math teachers, the consensus would be to train more math teachers. For some reason, that logic doesn't seem to apply to physicians.
If 1/3 of US physicians are born abroad (and they note that the analysis could not distinguish between physicians trained in their country of origin and those trained in the United States), there would seem to be scope for a substantial increase (like 50%) in the numbers trained in the US
and for those who care about such things
US med schools by race
mixed race 9%
US med schools by sex
seemingly, transgender/intersex/etc are not welcome at US med school