I would consider vetted vs unvetted to be a more important distinction than safe vs unsafe.

Rust has a trust model, and unsafe is an important part of that, but only a part. Unsafe means "the safety of this code relies on invariants not checked by the compiler." It does not mean "inherently unsafe." Rather, it means "trust must come from a different channel." This tool is providing such a channel.

If you want something that reports specifically on the use of unsafe code, then take a look at Cargo-Geiger.