For the sake of this discussion, I'm going with the nationalistic vibe of the order: anybody who isn't a citizen of the USA (presumably to limit risk of AI-supported action against the US?).
replyBut that in itself is telling in a way: if national security was a true concern, access should be limited to people who passed background checks.
Right - it doesn't hold up to scrutiny. For one, "not a citizen" is a pretty hard bar to assess online. For another, "citizen" isn't very meaningful here. Many national security incidents have featured a citizen at the core - and it's a really fuzzy indicator of "potentially hostile" and especially "for what reason".
replyI guess I'm possibly giving them too much credit, but if the people who sent the letter have their head screwed on straight, "protecting national security by disallowing specifically non-citizens from using it" can really only be read as a smokescreen, or at very best a small part of the actual picture.