If a man told you he worked with computers, it'd be odd to raise an eyebrow and respond "Are you some kind of computer boy?". The technician treated this woman's work as something special because she was a woman. In other words: A man that works with a computer is still just a man. A woman that works with a computer must be something special, a computer girl.
And bonus points for calling her a girl, which is just a little bit more infantilizing.
If a man told you he worked with computers, it'd be odd to raise an eyebrow and respond "Are you some kind of computer boy?". The technician treated this woman's work as something special because she was a woman. In other words: A man that works with a computer is still just a man. A woman that works with a computer must be something special, a computer girl.
And bonus points for calling her a girl, which is just a little bit more infantilizing.