BMX123: Grammar police
But this is not an instance of people being the "grammar police." Simply put: typing in all caps is incorrect and borderline rude to other participants, even if it is unintentional.
On an anonymous discussion board, I would think that people would be secure enough in themselves or have enough self awareness to simply reply, "Gosh, I didn't know that I was doing it wrong. My bad. Thanks for letting me know."