As has been noted in another comment, the article makes that statement, but skips over the implications of the constant apparent motion of the sun for the lengt

As has been noted in another comment, the article makes that statement, but skips over the implications of the constant apparent motion of the sun for the length of day. It gives the impression that, geometrically speaking, there is a day on (or near) the equinox which has equal darkness and daylight. Of course, this isn't guaranteed at all, and certainly not for every point on the earth's surface.