Publishers are a business, generally speaking. To address your edit: What is the upside to a publisher of publishing a book widely (though not universally) considered offensive? Especially if that books is aimed at children?

Clearly, they consider what demand there is to be not worth the expense and potential reputational risk of satisfying. You can say that this last part is a form of censorship - but in reality, it's just how cultures work. There are things which are considered taboo. You may do them if you wish, but you have no right to say they should be consequence free.