Gen Z linguistic phenomenon. It's to signify a more authentic or calmer, more personable style rather than an overly literary one. It's kind of nice actually, like talking to a friend about their thoughts.
Yes however I doubt the author was an IRC user. For chats people generay do use lowercase cause it's easier but this article is also about using lowercase outside of chats.
bauhaus in 1925 has been linked in a peer comment.
i've got a 1926 print book is 5 by e e cummings who famously often used lowercase in his prose and poems ... going back earlier than the collection i have.
https://www.theguardian.com/society/2025/feb/18/death-of-cap...