Why do they do this?

In reading about the so-called Child Custody Protection Act (you know--the punishment for having sex if you're under 18 is pregnancy, no matter what) I was looking for the party breakdown of the Senators supporting the bill, and I found this table setting out how the Senators voted by astrological sign.

This is the Washington Post! A newspaper with pretentions to being taken seriously! I know they publish a daily horoscope, but really, why would any newspaper do this?