This is so sad to hear
Just my thoughts : I'm having feelings that her management / avex decided to take control before something bad could happen.. It's a move to avoid the social media drama after some of the posts that were made by Ayu (you know... something like zayn malik vs the entire one direction fandom). I'm pretty sure Ayu can handle those negative comments, but maybe her management couldn't.
So keep sending her your love guys! and let's hope that there's another way fans can interact with her.