There’s nothing bigger at play. The reasoning is obvious. It’s because there are not enough masks available and it’s more important that healthcare workers get them right now than the general public.

Once healthcare workers are covered, then we can make sure everyone else starts wearing them.

The reason they've been telling us not to wear masks is a little tricky: they don't want us to buy N95s in lieu of having them go to medical staff.

From the BBC:

"Disposable surgical masks also are not recommended for people unless they're sick or caring for someone who's ill."

Well, if it helps someone caring for someone who's ill, obviously it will help a random person no? I suppose the issue is the degree of effectiveness, how it is used, and I've read that wearing a mask makes people otherwise too confident and lax in other things aks washing hands.

If Korea can do it, we can do it, whatever 'it' is it's not magic.