I mean, fangirls are annoying when they're always like "OMG I LOVEU ARTSU DESU!!" and such. And it's annoying when they CLAIM to be Japanese when they're not.. Like, I was in Japanese class for only one year cause I was interested in it, but then I ended up forgetting MOST of what I learned, but I do remember how to pronounce some things, and I never learned how to read Kanji. I'm not Japanese, but I do have a right to speak it if I please, and as long as I learn it properly. And no, I didn't join Japanese class just because "ANIMU DESU NE~!!" it was because I was honestly interested in learning more about the culture and life style!! The Anime stuff was just a plus, lol.
Okay yeah, saying those does not make a fangirl. I do agree to an extent that some fangirls need to calm down, but saying things like "kawaii" is either a weeaboo or just someone wanting to say it because they can.