But think about it this way. There are people in China who are not sick (went for vacation) and now are stuck. If all transportation is closed they are forced to become sick the eventually die. I understand that they might spread it if they come here but they get scanned for corona virus right when they get off the plane.
The virus takes about 2 weeks to show. That means thousands of people would have to be in temporary quarantine, and who's going to wait check all those people for Covid-19 symptoms? So while yes, it's pretty sad that uninfected people are forced to be stuck in an infected area, the virus has spread to other countries which is a direct result of people being allowed to travel. Once they start showing the symptoms it's already too late and that's how pandemics start.