I can't remember who stated that any good quality taken to the extreme becomes a crime but I always think of it when I hear of people putting themselves, their families and everyone around them at risk while practicing their 'altruism'.
A person who is driven by the ego of appearing or feeling good doesn't care for the consequences on others. I think it's selfish in the extreme to import a deadly virus into a country that doesn't need to have it. There is no reason why he shouldn't be treated in the country he picked it up. It pisses me off when people can't be happy just to sacrifice themselves, they have to endanger everybody else too.
What if all their precautions fail? It just takes one human error and the disease could spread in a city of millions. Ebola traditionally was a small problem because it was contained within tiny, remote and extremely isolated regions of Africa. Nobody knows the consequences of a city epidemic, the greatest risk would be the virus mutating to become more infectious. A small chance is still a chance and when the consequences are so deadly there's no excuse for taking that risk with other peoples lives.