From what I understand, Matt is suing because it's no longer critics, it's online harassment that has been going on for almost 2 years. She doesn't mind the critics, she understood that came with her work, but harassment is something different. Funny enough once they know she is collecting evidence, they started to grovel and apologize
I guess it's similar to what Pope had to endure previously, the constant online harassment send through private messages for almost a year to his social account, only he didn't sue, he collected the evidence and send the police for warning.