Look at the source.
I'd be very cautious about accepting reports like this. The results in surveys of social behavior are often distorted by those doing the survey, in order to prove one particular thesis or another. (Look at the famous Kinsey report, for example, which was an outrageous manipulation of data, skewed to support Kinsey's own theories.)
I think this is the exact line used in Jeff Dahmers scool transcrips