chapotraphouse

EXACTLY. It's their entire schtick. "We are normal. We are proper. We are the defenders of virtuous civilization." This is their outward creed. Pointing out that they are obsessed with people's genitals and things that slaps them in the face. It makes them outsiders. There in inferiority associated with being weird. There is a sense of ostracism associated with it.

And as others have pointed out is also is such a common word that everyone in America can associate it with an icky feeling about someone. Everyone has used the word. Everyone has experienced weirdos in their lives. It is an instant association.