I think I strongly disagree with your first sentence. Strongly. I've worked with enough people with fine coding skills and terrible English to know that the two are not an uncommon combination. Last year, I worked with someone whose first language was something from China - no idea which flavour - and they would often pass their written comms through an LLM. I could tell when they had done so by the onset of sudden grammatical correctness. But I don't think they were doing this with the intention of deceiving, merely of communicating clearly and correctly.

Now, I often find Claude's idea of idiomatic prose to be a bit load-bearingly seam-hitting as it lands not this point, but THAT one, but it is probably better than something hacked out by a person who confuses tenses, cases, pronouns and when they can enverb a noun. So I tend towards giving people the benefit of the doubt on this.

Lastly, if you think LLM-written software is full of security vulnerabilities and bugs, I have terrible news for you about the state of human-written code. The fact that what we do is often better than nothing at all, is no big recommendation.