It's important to note that challenges or attempts to ban books often occur due to various reasons, such as concerns about controversial content, explicit material, or differing ideologies. If there have been any challenges or bans related to "50 Sculptures You Should Know," it would likely depend on the specific objections or controversies that individuals or groups may have raised regarding its content.

In general, those who object to books being banned often do so to protect freedom of expression, intellectual freedom, and the diversity of ideas. They argue that restricting access to books limits the opportunity for individuals to explore different perspectives, engage with challenging or thought-provoking material, and make their own informed judgments. Advocates for free expression believe that it is essential for a democratic society to have access to a wide range of ideas and viewpoints, even if some of those ideas may be controversial or unpopular.