So let's talk about that. Well written C code, especially for the purpose of writing and continuing to maintain mature GNU coreutils, is not a big risk in terms of CVE. Between having an inexperienced Rust developer and an extremely experienced C developer (who's been through all the motions), I'd say the latter is likely the safer option.
The software with the best security track record of all time is written in C.
> I'd be interested in a comparison with the amount of bugs and CVE's in GNU coreutils at the start of its lifetime
The point is, those bugs had been discovered and fixed decades ago. Do you want to wait decades for coreutils_rs to reach the same robustness? Why do a rewrite when the alternative is to help improve the original which is starting from a much more solid base?
And even when a complete rewrite would make sense, why not do a careful line-by-line porting of the original code instead of doing a clean-room implementation to at least carry over the bugfixes from the original? And why even use the Rust stdlib at all when it contains footguns that are not acceptable for security-critical code?
For a project of this kind, this seems a rather stupid choice and it is enough to make hard to trust the rewritten tools.
Even supposing that replacing the GPL license were an acceptable goal, that would make sense only for a library, not for executable applications. For executable applications it makes sense to not want GPL only when you want to extract parts of them and insert them into other programs.
Perhaps one good reason is that once the initial bugs are fixed, over time the number of security issues will be lower than the original? If it could reach the same level of stability and robustness in months or a small number of years, the downsides aren't totally obvious. We will have to wait to judge I suppose. Maybe it's not worth it and that's fine, but it doesn't speak to Rust as a language.