The words "national ground stop" are quoted a few times in the article. If that terminology got back to various airline dispatchers, it may have been more broad than a few airports.
It's possible that controller may have just misspoken or been fed words from another controller and said 'national' when in fact it was for the west coast centers (ARTCC) only (Los Angeles, Oakland).
The original article makes it seem like a very local event from “a regional air traffic control facility” mentioning a few individual conversations with pilots. I guess in theory pilots could have said something to their airlines but that’s not a big window for the airlines to actually do anything.