The complaints I remember seeing are that she's always "leeching" off the dudes and ignoring the girls, that she's incapable of controlling her "corporate SJW" outbursts ( You can't be a fan if you don't respect pronouns, entitled incel type shit), and that during a Russian-language stream she said she's glad she's not in HoloEN because then she'd be forbidden from doing non-English streams. That's not true. So she DMCAs clips of it.
All plausible. Can't testify to any of it, though, because I think Niji hiring her is about analogous to Rockstar hiring Anita Sarkeesian at the height of "gamergate," and why would I want to watch that?