Part I-- for non-US citizens travelling to the US
1) if the US institutes travel restrictions, they will come anyway but most likely illegally over the border and we won't be able to track them. (there are multiple fallacies in this argument)
2) It is better to let them come here, and treat those who become ill here. (except that no one can accurately predict how many infections would occur, and the current US response is probably not deliverable if there were several hundred or thousand infections in one metropolitan area.)
Part II-- for US medical personnel who volunteer to go to Africa
1) the disease is best fought in Africa, so we should encourage qualified personnel to volunteer their services(probably true)
2) a quarantine upon arrival back to the US, will either stigmatize those volunteers unfairly or discourage them from going in the first place. (I have a very hard time believing this-- and so far we have seen no stigma attached to those US citizens who have recovered from the disease.)
RE: if the US institutes travel restrictions, they will come anyway but most likely illegally over the border and we won’t be able to track them.
Did he explain how an ebola infected person from Liberia without a US visa can come to the USA or even Mexico?