That statement is incorrect.

It's harder to write unsafe code in Rust. That doesn't make it "unsafer". What I mean is this, if you want to write unsafe code in Rust the C++ way, your entire program has to have unsafe markers everywhere. It's just as unsafe as C++ at that point.

But if you want to write unsafe code in Rust the Rust way, you run into a requirement that didn't exist in C or C++: The abstraction around the unsafe code must be safe for you to drop the unsafe marker. This created a unique category of abstractions that no other language has, so if you are working on unsafe code in Rust you are often a pioneer doing something never done before.