"People who censor books are usually illiterate." --John D. MacDonald
I've no empirical data, but I have anecdotal experience with people who censor comic books and yes, they are illiterate.
... A high school senior, male, borrowed a comic book called "Arrowsmith" by Kurt Busiek and Carlos Pacheco, clearly labeled "for mature readers"-- about PG-13. "Arrowsmith: So Smart in their Fine Uniforms" is an alternate history of World War One-- if magic had been used as a weapon. The student's father brought "Arrowsmith" back to the school and withdrew permission to borrow books, NOT because of the explicit World War One gore-- the book's main theme is the loss of innocence-- but because of shadowy panels of a nurse making love with a soldier (shades of Ernest Hemingway and "A Farewell to Arms"). Sex bad, violence okay; Lenny Bruce used to complain that the violence in "Psycho" was permitted, but Janet Leigh's bare breast was forbidden.
The same father told the teacher that as far as he was concerned, "Where we really went wrong was back in the Age of Reason, because that's when religion started to veer off from daily life." If I'm lying, I'm dying. There are at least two witnesses.
In another case, a parent complained about "Death: The High Cost of Living" by Neil Gaiman. This is a variation on "Death Takes a Holiday", with the Reaper spending one day a year as a mortal in order to experience death herself. Two of the characters are "lesbians". Thank God this parent never saw Gaiman's "use a condom or die" message involving a banana. Censors never seem to actually read the books they complain about-- they just skim for the dirty pictures. Don't they know what that says about them?
I also worry about the souls of adolescents so trained to go running to the church police if they see anything upsetting. Shades of the Nazi Youth Movement, with every deviance reported! In Benton Harbor we were made of sterner stuff. Uncensored material was cause for celebration, and could only add to a book's popularity.
...The dastardly author, Neil Gaiman, was kind enough to e-mail his support to the teacher. The book, "The High Cost of Living", is still listed as a "recommended book for teens". The student took the book -- clearly labeled for mature readers-- off the teacher's desk without permission, but the teacher clearly should have been more... limited?
... A Sherman Alexie book of short stories, "The Lone Ranger and Tonto Fistfight in Heaven" was banned from the same high school because of language; too bad, since it was recommended in a Western Michigan University adolescent literature class.
I'm told by teens that if you say the F word once in a movie, it's still PG-13; any more than that and it's rated R. They learned this from watching John Travolta in "Stay Cool".
Lastly-- you're gonna love this one-- a high school teacher was told not to read "Mr. Roberts" in drama class next year, because the sailors talk (mildly) about booze and nurses. Yes, that's right-- the World War II, Greatest Generation, Henry Fonda, Jack Lemmon, William Powell and Jimmy Cagney "Mr. Roberts". [Well, he wouldn't let his mind be put in prison, for one thing. Sadly, the nimrod in the photo was trying to evoke Mr. ROGERS-- Oh Literacy, Where Art Thou?]
This is just one year in one rural district in Michigan. Earlier complaints were made against "The Witch of Blackbird Pond" and "To Kill A Mockingbird"-- not because of the rape trial, but because Scout said, "Pass the damn ham!" School administrators in small towns are notoriously afraid of conflict. American schools emphasize sports, so the kids who love books and their parents have no real pull in the community. These same children, like their peers, report watching R-rated movies and worse-- but hypocrisy is a way of life here. Better to be an American Idiot than be called a pornographer.
Alas, public schools are for the most part under control of people who hate books, ideas, and independent thought. Censors especially fear the sight of a bare breast; perhaps they are more reptilian than mammalian. I'll save you a spot in the detention camp.