It’s no secret that companies scrutinize their customers’ online habits, drawing inferences for targeted advertising. Last week, Twitter announced a new transparency tool seeking to demystify the process—and promptly found itself under fire for “cissexism” and “egregious rhetorical violence” against transgender, non-binary, and gender-fluid and gender-nonconforming users.

Like many tech companies that cull data about users’ activity and use machine learning to gain insights, Twitter develops individualized profiles to make ads better fit the unique interests and needs of its users. Those individual profiles include Twitter’s guesses about users’ age range, languages, preferred mobile phones—and, controversially, gender.

Users are also able to edit profile data, and in addition to “male” and “female,” Twitter has an “add your gender” option.

That’s not enough for many of its critics, who say the company has caused them emotional trauma by assuming people’s gender. “Hey, Twitter, it’s bad enough that you enforce a false gender binary, but actually misgendering folks is egregious rhetorical violence,” one user wrote.

Another user said the gender assumptions were “bulls*t stereotypes,” while another said they were “outdated cissexist binary-centric bulls*t.”

“Apparently Twitter thinks it’s okay misgender a few million users,” one user wrote. “Cissexist much?”

Another Twitter user vented about being “assigned male”—“even though my pinned tweet literally says ‘I’m not cisgender. I’m genderfluid.’”

Twitter declined Heat Street’s request for comment on the controversy.

— Jillian Kay Melchior writes for Heat Street and is a fellow for the Steamboat Institute and the Independent Women’s Forum.