I'm not sure that is the case in this instance. Certainly general writing is a lot more variable and harder to classify, and on the other extreme certain one-line code changes don't have enough information to say anything. However, a blob with a 500+ line code change and 200+ lines of comments is a dead ringer for some of the current class of LLMs. That isn't to say it this behavior couldn't be obfuscated, but some basic categorization could probably separate the majority of human authored commits vs. AI commits. Heck, you could probably train an AI to detect commit-style just by using pre-2022 code archives and existing known-to-be-AI edits/commits.