Because it's technically true. The best kind of true!
Sorry, I meant to say the opposite of truth. Neither Rust nor Ada.Spark, which use LLVM as a backend, can prove via that they are correct if LLVM has bugs.
In the same way, I can't guarantee tomorrow I won't be killed by a rogue planet hitting Earth at 0.3c. So I should probably start gambling and doing coke, because we might be killed tomorrow.
> Every single project needs to "fix" the same kind of safety issues over and over again
I doubt that's the biggest problem. Each of the unsafe libraries in C/C++/Zig can be perfectly safe given invariants X and Y, respectively. What happens if you have two (or more) libraries with subtly non-compatible invariants? You get non-composable libraries. You end up with the reverse problem of the NPM world.