Sure, but there are natural guardrails within that... for instance if we decided to call the UK a country of national security concern it would trigger massive diplomatic and trade ramifications. Other than China you'll notice everyone else on the list basically has 0 trade volume with the U.S., so there's not much damage to the U.S. economy, but doing it to other countries would be a major escalation with economic consequences.
How would that be possible? I've read the text and didn't see any ability for them to not publish it, but more practically as soon as they ban an app from X country not already on the list, wouldn't it become clear in their justification for doing so that the country of origin would have been added?