They don't, hence the suspicion instead of a definite assertion. And suspicions are easy, because what are the consequences if it's false? None.

Anyway your comment smells AI generated, I can tell from some of the pixels and seeing quite a few shoops in my time.

I don't need to "prove it", because all I have to do is link this:

https://arxiv.org/abs/2409.01754

https://arxiv.org/abs/2508.01491

https://aclanthology.org/2025.acl-short.47/

https://arxiv.org/abs/2506.06166

https://en.wikipedia.org/wiki/Wikipedia:Signs_of_AI_writing

https://osf.io/preprints/psyarxiv/wzveh_v1

https://arxiv.org/abs/2506.08872

https://aclanthology.org/2025.findings-acl.987/

https://aclanthology.org/2025.coling-main.426/

https://aclanthology.org/2025.iwsds-1.37/

https://www.medrxiv.org/content/10.1101/2024.05.14.24307373v...

https://journals.sagepub.com/doi/full/10.1177/21522715251379...

https://arxiv.org/abs/2506.21817

Either they used an LLM to write part of it, or the linguistic mind virus infected them and now they speak a little bit like an LLM.