Under the American Library Association's definitions, presumably it would be. I wouldn't say that -- I don't think removing a book from a school library is properly called "banning," and I don't think it should be seen as violating the First Amendment (notwithstanding the opinion of four Justices in Board of Ed. v. Pico (1982)). Here's the full story, from Eric Muller (IsThatLegal?):
Not long ago my daughter came home from public elementary school with "Journey to Japan," a book she had checked out of its library. My daughter is in the third grade. The book is not simply available, but on a special shelf of books that kids get a sort of "extra credit" for reading and answering questions about. . . .
(. . . I have asked that my daughter's school remove this book from its shelves, and they have done so on at least an interim basis while their library committee reviews it.)
In Journey to Japan, a home-schooling American Christian family travel to Japan. There they meet a Japanese girl named Yoko. The American family quickly learns that Yoko is in some sort of conflict with her parents, especially her stern father.
The American kids keep hearing about this strange religion called "Buddhism," but don't know anything about it. The main thing they learn is that Buddhists worship many gods, not one. "What if they choose not to believe in Buddha?" the young protagonist asks an American adult. "They don't have that choice," the adult explains. The protagonist confesses that she finds the Japanese religion "confusing."
The conflict between Yoko and her father intensifies through the book, and the reader learns that Yoko is stealing off to some undisclosed location each night. The American kids learn that Yoko's father condemns her as a "rebel" and a "bad person."
There is some discussion among the Americans about Buddhist and Shinto religious practices, and the protagonist comments that these practices "all seem kind of confusing." "That's probably why Yoko won't go [to the Buddhist and Shinto services] anymore," an adult explains.
The source of the tension between Yoko and her father is revealed in Chapter 9, when the Americans go to a Japanese Christian church and find Yoko there.
It suddenly dawns on the protagonist: "Yoko was not a bad person-—she was a Christian!"
Yoko explains her situation to the Americans: "When I was a little girl, I went to a church down the street for Bible school on Sundays. My parents let me go. . . . It wouldn't hurt me, they'd say. By the time I was twelve or thirteen, I was sure that I loved Jesus and wanted to be part of God's family. I read my Bible and prayed. In the last few years, I knew I could not keep going to the Buddhist temple and the Shinto shrines. I do not believe in many gods. I believe in only one."
"I love my family," she explains, "but I love Jesus more."
At the end of the book, Yoko comes knocking on the American family's door, explaining that her father has turned her out. Everyone prays, and the American father assures the worried children that God will take care of Yoko, "just like He cares for us."
Yoko ends up deciding to come to America. "It still hurts to be away from my family," she says, "but I know God is taking care of me."
The book's dedication is "To our friend and sister in Christ, Yoko."
A few thoughts:
I think there's no Establishment Clause problem with a school library's keeping the book on its shelves. (Recall that though Eric objects to the book's being on "a special shelf of books that kids get a sort of 'extra credit' for reading and answering questions about," he asked that the book be removed altogether.) Though the library does in some measure endorse the books in the library as fitting reading, it doesn't endorse all the views in those books as being correct. Parents can easily explain this to their children, and I think that many third-graders can figure this out even on their own. For that matter, I would hope that one things school teach is that not everything that's written in a book -- even a school library book -- is true.
Moreover, if the Establishment Clause does bar school libraries from stocking such books, then this wouldn't just apply to books whose primary focus is pro-religious -- it would also apply to books that have some religious themes (try the Chronicles of Narnia), or even books in which some appealing characters are religious, and express their religious views. Would even the Christmas Carol be immune? Courts ought not, I think, read the Establishment Clause in a way that would demand the exclusion of such views from school libraries.
At the same time, I think it's probably bad judgment for the public school library to include books that overtly criticize (even mildly) other religions -- at least for the lower grades -- unless the books have such great historical or literary value that they need to be included. Naturally, people are free to express such criticisms outside school, and many religious belief systems necessarily involve implicit and often explicit criticisms of rival systems. Still, it seems to me that public schools ought to try to teach tolerance of other religions, and the most effective likely way of doing that, at least for lower grades, is by not carrying criticisms of those religions.
Adults and even teenagers need to learn a complex mix of tolerance of others' beliefs but a recognition that those beliefs may be wrong, even deeply wrong. But for third-graders, I think, the best way of learning that, at least in a public school, is by stressing the tolerance, and not focusing on the beliefs' supposed error. Also, though, I'm no expert on Buddhism, I'm not sure that the book's description of Buddhism is quite correct, which may be another reason the school shouldn't carry it.
Nonetheless, these are matters of judgment about education policy, morals, and manners, often involving subtle differences of degree. They ought to be decided by school administrators, subject to moral suasion by parents and by the public, not by courts.
What about putting religiously proselytizing books -- assume for now that they don't include explicit or obvious implicit criticisms of other religions, or of irreligiousness -- "on a special shelf of books that kids get a sort of 'extra credit' for reading and answering questions about"? I think this too is not unconstitutional (though neither is it constitutionally mandated).
Moreover, it seems to me that many religious parents (and maybe even some religious kids) would like to have this as an option for their own kids; other kids are getting extra credit for reading about things that they or their parents find interesting or enlightening, and the religious parents may want their kids to get extra credit for reading about things that they or their parents find interesting or enlightening. Nor do I think that there's anything unconstitutional -- or educationally sound or otherwise improper -- in the school's facilitating this.
But, some parents may say, my child is being exposed to religious beliefs I disapprove of, without my knowledge or permission! So? The child will be exposed to lots of religious beliefs in lots of contexts, many with much more pressure (say, peer pressure from classmates) than that provided by one of many library books (or even one of many library books that one can read for extra credit). It seems to me that parents have plenty of time, authority, and power to counteract this, by explaining to the child that while others believe the things in the book, they (the parents) don't believe it, and by explaining why the child shouldn't believe it.
In fact, this may give the parents a good opportunity to actually strengthen their teaching of their own religious views to the child: It's often confrontation with rival religious views, and an explanation of why those views are supposedly mistaken, that helps reinforce in the child the parents' views.
Now I can certainly understand why some parents might nonetheless not want their children exposed at school, or in the school library, to a favorable, emotionally persuasive presentation of these rival views (whether religious or political). That's one reason that I don't think schools should be barred from removing books. But I don't think they should have a constitutional obligation to remove them. And I think that people who are in a religious or political minority should expect that their child will indeed be exposed to the majority's views in the school library -- and though they can try to persuade the majority that the books should be removed, they should have no legal or moral entitlement to having those books removed.