Not every book is fit to read. Filth, pornography, etc. can be, and should be, avoided by entities that spend public money. If you want those, you can pay for them yourself, but they are available. There have been many conservative leaning books that had high interest from the public that publishers refused to publish, that stores and mail order outlets refused to carry. Books that are loaded with footnotes, easily researched. No filth, no propaganda, just truth, and they try to deny access to them.
In any case, the government does not ban or burn books, they just leave some of them for you to obtain on your own.