I suspect that at least in part, the fad in the AI community of using all-lowercase is to make sure that their writing can't be mistaken for LLM-generated outpu

I suspect that at least in part, the fad in the AI community of using all-lowercase is to make sure that their writing can't be mistaken for LLM-generated output. Sam Altman more than anyone else popularised this style and for a while every thrid or fourth comment on any AI-related topic was all lowercase.