Ohh, poo says nothing – it is expletive. Pointless. An utterance.
But an expletive does still say something though, in my opinion. It expresses an emotion.
I get this same nonsense from the missus. I moderated my language to avoid swearing, but I get pulled up for saying things like “Bloody hell” or “Damn”.
In my experience saying something like “I say Timothy. I seem to have trapped my fingers between this oily bicycle chain and the sharp teeth of this rather worn cassette. That really is frightfully painful.” doesn’t convey the same urgency or emotion – which means the expletive is actually better communication.