I think the specific language in question - perl - is really the source of OP's frustration. Perl is kind of like Regular Expressions - much easier to write than it is to read. I would expect LLMs to struggle with understanding perl. It's one of the best languages for producing obfuscated code by hand. There are many subtleties and context-dependence in perl, and they aren't immediately apparent from the raw syntax.

Edit: I totally agree with your point about not wanting to learn a language. That's definitely a situation where LLMs can excel and almost an ideal use case for them. I just think that Perl, in particular, will be hard to work with, given the current capabilities of LLM coding tools and models. It might be necessary to actually learn the language, and even that might not be enough.