I agree it is an exaggeration in that of course you could write a wrapper. The point was that if everyone had to write their own FFI wrappers, Rust wouldn't go far and openat is not an exception.

There is code available at the right level of abstraction (the rustix or openat crates), and while it's not managed by the Rust team, uutils already have many third party dependencies. Bringing up libc just because it's first party, instead, is comparing apple to oranges.