Spoiler: the title is clickbait and the article actually says that C isn't really slower.
The initial C implementation written by the author that was passed off as representative of C was naive and had a couple of performance blockers. The author points out those performance blockers, and once the author gets rid of those blockers and re-tests te conclusion is that C isn't actually slower.
The initial C implementation written by the author that was passed off as representative of C was naive and had a couple of performance blockers. The author points out those performance blockers, and once the author gets rid of those blockers and re-tests te conclusion is that C isn't actually slower.