Everything is Sexist
Some things are beyond parody. It does not mean one ought not parody them:
My wife and I had a four minute argument over whether the woman quoted at the outset is part of the parody or not. She is indeed being serious: for that is Miss Anita Sarkeesian of Gamergatehate fame.
So her claim that Gamergate is sexist, in effect, is the claim that Gamergate exists.