"This legacy C code" usually has millions of lines. "The unsafe parts" are usually on the few dozens.
The safety is also conditional on rustc not having bugs, and your computer working correctly. But you don't get to pretend those are as risky as some large random, less used C code.
Not only that but also the clear boundary of responsibility. If there’s a way to use a library in safe Rust that cause UAF, that’s the library problem. In C, it’s because you are using it wrong.
The safety is also conditional on rustc not having bugs, and your computer working correctly. But you don't get to pretend those are as risky as some large random, less used C code.