I thought this immigration ban was taking place independent of the visa process. I understood this ban to happen even for people with valid visas and even valid green cards. If this was "just" about visas not being granted the process would be much less of an issue. People would have found out long before they got to the border and people with existing green cards, etc. would be fine. But for some reason that couldn't happen and we had to rush into this half thought through mess.
Again, that happened in a far away land to people I don't know. The issue at hand is about people with green cards and H1Bs not being able to enter the country because Trump had a bad hair day. Completely different, I work with the latter people, while the former I don't know.