The media have been bloviating on this very subject. According to them, travel bans don't "work". Obviously, they do work - if nobody had left China, neither would SARS-2 - but the criticism is coming from a pseudo-ethical perspective rather than a sound scientific one.
The point they're trying to hammer home seems to be something about xenophobia and how it's more important to be politically correct than to prevent and/or survive a pandemic. I'm glad they're sticking to their principles and not being hypocritical about all of this: it is indeed better to die than to hurt someone's feelings.
Anyway, if Trump of all people proposed a travel ban, the media would be metaphorically crucifying him (I mean, more than they do already). It would be like a perfect storm to them. Meanwhile, China, a homogeneous totalitarian nation, is just embarrassing Western democracies with its efficiency. Imagine trying to create a new hospital within a week in Britain, let alone two.