I was thinking it's their funny way of saying "the type of soda which there is the most cans of inside the machine".
Like maybe they programmed it to just take whatever item is least popular so that they don't run out of the more popular ones too quickly. But maybe the machines don't actually know how many of each there are inside idk
I'll explain it for ya real quick. So you'll run into scenarios like this. Imgflip is the place of memes so it's normal. You can even do it too! But yeah. For someone like myself that wants to go on and on i won't for your sake. So this is as simple as i can put it