A senator^Wcongressman asked some questions about Rust and its nightly toolchain whenever Facebook’s cryptocurrency was under scrutiny by regulators. A French government agency has a whole set of coding guidelines for Rust. The government of Quatar was using Rust before 1.0; haven’t heard much since, but I assume they’re still using it. A New Zealand firefighter company was using some Rust.
Programming languages are tools. Governments use tools. It shouldn’t be surprising that they may have an interest.
That said I find your parent comment also a bit silly for the other reasons you state.
They care deeply about software security and memory flaws (everyone should). If rust had an ISO standard, then it could be used in more sensitive military and aerospace systems.
Something being an ISO standard has nothing to do with being able to send OFAC after you? Fundamentally the difference is providing a service vs an idea just existing in the ether. You can't sanction Rust, it's just an idea. You could tell rustup they can't allow downloads from IPs that match sanctioned countries.