So why do they need Rust then? What advantages does it provide? That was the main point of the article — we all wanted a better language, but got another crappy one instead.
That Rust didn't prevent one error in one specific instance does not mean that Rust didn't prevent any errors across any instances. Nor does it mean that Cloudflare didn't benefit from Rust in some way(s) elsewhere.
For example, from one of Cloudflare's previous blogposts [0] (emphasis added):
> Oxy gives us a powerful combination of performance, safety, and flexibility. Built in Rust, it eliminates entire classes of bugs that plagued our Nginx/LuaJIT-based FL1, like memory safety issues and data races, while delivering C-level performance.
[0]: https://blog.cloudflare.com/20-percent-internet-upgrade/
No programming language should get flak for a bug that is not the fault of the programming language. This is Cloudflare's problem.
If you're going to criticize something, at least do it properly.
The move to Rust was partly motivated because it prevented that entire class of errors. No more out-of-bound reads, or data races. The compiler audits these missed spots.
Now, you could say a managed memory language would suffice as well. Perhaps it could. But we needed performance, and no memory-managed language met those performance needs then or today.
I get you're making the case that Rust isn't perfect for all use cases, but Cloudflare's scenario is the exact corner case your argument falls apart in: we needed fast and safe in an environment where not being fast or safe had real business consequences, and nothing else except Rust gave both.