This statement makes no sense to me. "Being sexist" encompases an absolutely huge range of behaviors. It could mean something as small as making a dumb assumption about what type of aesthetic preferences someone has, to something as large as making hiring decisions that can permanently stunt someone's career growth. It could even mean promulgating laws that legitimize violence against people.

Sexism is thus a category of bad behaviors, some of which are worse than anything I could imagine stemming from being accused of sexism. I am not saying that being falsely accused of sexism is nothing. It certainly would make me angry and frustrated to be so attacked. I just think false accusation of sexism is worse than the least severe forms of sexist behavior, and better than the most severe forms of sexists behavior.

Asserting that false accusations of sexism are always worse than sexism seems obviously false.