When do you need files e.g. named O.txt and o.txt in the same directory? Won't you yourself be confused by them? It's the simplest example and it already shows that case sensitive file systems bring nothing but confusion.
Anyone arguing for case-insensitivity has to both a) demonstrate that this is a source of confusion in the real world, by actual people using computers in UIs that exist today, rather than "when I think about it that's kind of weird because it doesn't behave like Windows" or hypothetical oh-dot-texts and b) come up with a better plan that handles the world outside of US ASCII.