Isn't it obvious, teh RIAA felt bad about the world pooping on Joanne and decided to throw her a bone for a song back from when her and certifications were still friends
"With this award, Lady Gaga joins a prestigious and exclusive list of Gold and Platinum luminaries. 'Bad Romance' is one of the most popular and iconic songs of the last decade. We are honored to present Lady Gaga with a Diamond Award in recognition of 'Bad Romance' surpassing the ten million mark, and to congratulate her as the first female artist in Gold & Platinum Program history to earn a Digital Diamond Award."
Bad Romance was the first song to do this, as it came out before those other things some of you are listing. Gagz again.