Hi, original author here. As someone above said, I guess I didn't introduce the context well enough to answer why it's a gender issue. The blog post is a snippet from a larger research paper I wrote examining the role of computer science classes in high school in getting more girls into computer science as a field. I don't mean to imply that females are dumb, and I didn't mean to imply that computer science classes treat boys differently than girls (although they frequently do).
The reason the lack of accurate class nomenclature affects girls more than boys is that boys have more interest in and experience with using computers than girls do by the time they enter high school. It's caused by a combination of factors, such as parents encouraging boys' computer use, boys' interest in video games, and the mysterious "magnetic attraction" to computers that more boys have than girls. (I pulled this info from the book Unlocking the Clubhouse which used 90's data, so this average may have changed since then, but I don't think by much.) So by the time they enter high school, boys tend to have more advanced computer skills than girls. This means that high school computer classes play a greater role in influencing girls' perceptions of computer science than boys'. That's why it's a gender issue.
You're right, I should have clarified that in the article.