It's not just that they didn't mention why they fired her, it's that they didn't seem to have any plan in place to handle the work that she did, or indeed enough clue about her job to understand that they even needed one. If I remember correctly, one celebrity literally flew out to New York to do an AMA with her assistance and found when he got there that she'd been fired and it wasn't going ahead, and the admins didn't handle the other future AMAs that were relying on her any better.