I’m not a native English speaker so I checked on the definition of reliability

  the quality of being able to be trusted or believed because of working or behaving well

So for generating text, LLMs are very reliable. And they do a decent job at categorizing too. But code is formal language, which means correctness is the end result. A program may be valid and incorrect at the same time.

It’s very easy to write valid code. You only need the grammar of the language. Writing correct code is another matter and the only one that is relevant. No one hire people for knowing a language grammar and verifying syntax. They hire people to produce correct code (and because few businesses actually want to formally verify it, they hire people that can write code with a minimal amount of bugs and able to eliminate those bugs when they surface).

I'm a native English speaker. Your understanding and usage of the word "reliability" is correct, and that's the exact word I'd use in this conversation. The GP is playing a pointless semantics game.