Well, my thinking was: Euroclydon's friend likes to be technically correct about the term onomatopoeia, and jimmyk chimes in with the same level of technical correctness on the matter. So for levity, I point out how it is 'ironic' in a nonsensical way - hoping to hit their OCD nerve a bit. As it is clearly not an ironic statement, and we only have anecdotal evidence of cucumbers being able to mutter a sound.