“When you look at the banned book lists and specifically the stuff that’s being allowed, there’s a definite bias toward violent armed white supremacy and the censorship of anything that questions the existing religious or political status quo,” said Paul Wright, the executive director of the Human Rights Defense Center.

Activists see bans as an indictment of how prisoners are limited more broadly. Amy Peterson, a member of NYC Books Through Bars, which sends books to inmates in 40 states, said books were often sent back with little explanation.

“It does seem very much up to the person in the shipping room who’s making these arbitrary decisions,” she said. “I see it as one of the many ways that people are deprived of basic rights in prison.”

But for many incarcerated people, the ban on “The New Jim Crow” does not seem arbitrary. In 2014, Dominic Passmore, a prisoner in Michigan, ordered the book after checking to make sure that it had not been banned in the state. When it arrived, according to state documents, the prison’s mailroom staff refused to give it to him, citing its racial content.

Months later, after a series of appeals, the state decided that Mr. Passmore could read the book but informed him that he would have to buy a new copy, as it had misplaced his.

Mr. Passmore, who spent nine years behind bars after pleading no contest to armed robbery charges when he was 14, eventually read the book. He said that it opened his eyes to the wrongs done to black people.