the title should be 'weak DARK squares' not light squares. In the paragraph explaining the position, it also refers again to blacks weak LIGHT squares instead of DARK.
Yeah. The notes in the side said that before the initial position white had played Bxf7 Kxf7. This is probably the reason for the title. You are not wrong is saying that there are weak black squares as well though.
In this lesson http://www.chess.com/chessmentor/view_lesson.html?id=1606
the title should be 'weak DARK squares' not light squares. In the paragraph explaining the position, it also refers again to blacks weak LIGHT squares instead of DARK.