The original statement of NPOV was to at least mention any significant view supported by a significant minority of experts or people involved; not EVERY topic. It makes sense that, if you want the encyclopedia to be a starting point for investigating a subject, it informs you of the existence of significant non-sanctioned views.

In practice, this need is usually satisfied by the Talk pages and archives. The published article is sanitized, but if you really want to learn about the controversies in the topic, your best choice is to dig deep in the discussions that resulted in the controversy being excised from the visible version. It's quite rare that the talk pages are also purged as well.