I don't think people should be obligated to spend time and effort justifying their reasoning on this. Firstly it's highly asymmetrical; you can generate AI content with little effort, whereas composing a detailed analysis requires a lot more work. It's also not easily articulatable.
However there is evidence that writers who have experience using LLMs are highly accurate at detecting AI generated text.
> Our experiments show that annotators who frequently use LLMs for writing tasks excel at detecting AI-generated text, even without any specialized training or feedback. In fact, the majority vote among five such “expert” annotators misclassifies only 1 of 300 articles, significantly outperforming most commercial and open-source detectors we evaluated even in the presence of evasion tactics like paraphrasing and humanization. Qualitative analysis of the experts’ free-form explanations shows that while they rely heavily on specific lexical clues, they also pick up on more complex phenomena within the text that are challenging to assess for automatic detectors. [0]
Like the paper says, it's easy to point to specific clues in ai generated text, like the overuse of em dashes, overuse of inline lists, unusual emoji usage, tile case, frequent use of specific vocab, the rule of three, negative parallelisms, elegant variation, false ranges etc. But harder to articulate and perhaps more important to recognition is overall flow, sentence structure and length, and various stylistic choices that scream AI.
Also worth noting that the author never actually stated that they did not use generative AI for this article. Saying that their hands were on the keyboard or that they reworked sentences and got feedback from coworkers doesn't mean AI wasn't used. That they haven't straight up said "No AI was used to write this article" is another indication.
0: https://arxiv.org/html/2501.15654v2