I've pointed this out a lot and I often get replies along the lines of "people make mistakes too". While this is true, LLMs lack institutional memory leading to decisions. Even good reasoning models can't reliably tell you why they wrote some code they did when asked to review it. They can't even reliably run tests since they'll hardcode passing values for tests.

The same code out of an intern or junior programmer you can at least walk through their reasoning on a code review. Even better if they tend to learn and not make that same mistake again. LLMs will happily screw up randomly on every repeated prompt.

The hardest code you encounter is code written by someone else. You don't have the same mental model or memories as the original author. So you need to build all that context and then reason through the code. If an LLM is writing a lot of your code you're missing out on all the context you'd normally build writing it.