I honestly don't know what to make of that phenomenon. I never heard any voices, and I have Fi. If they didn't send them subliminally via smartphones, as someone here suggested, I'm not sure I'd count them as part of the propaganda attack that came up with all the other slogans. In fact, I'm not sure you can create a slogan for the introverted functions. Si is an exception because it refers to past experiences for its estimations of what's safe, and they could play the 'your past vaxxes did you good, too' card.