Just Say No to Kaus

Mickey "Misdemeanor" Kaus, a one-man involuntary abstinence movement, writes:

Is the 'chastity' movement and "abstinence" education all that widespread--especially outside the South?

Can anyone explain the use of single quotation marks around the word chastity and the double quotes around abstinence? Can anyone explain the use of any quotation marks in that sentence?