I don't think they're being pointlessly pedantic. I've been around POS systems and some people call it by the letters, P.O.S. & others by the acronym, sounding like "pause". Nobody assumes you're talking about a Piece of Shit when you say "pause". Also for OOO ("oooh") vs O.O.O., which doesn't roll off the tongue, but you don't sound like Casper.
Now, being pointlessly pedantic, I find it interesting to think that if we continue to use the word acronym for initialisms, then the word acronym will actually be initialisms! English is weird!