The "You may not use or adapt this material for any commercial purpose, such as to create a commercial database or database-as-a-service offering" language suggests that they think the license covers more than just distributing the document, which I believe is an unusual interpretation of what a spec copyright allows the author to prevent.

Lawyer repellent (I hope): The quote comes from https://github.com/mongodb/docs/commit/50e48200cde7e2eaffdc6... , and anyone who receives this comment may copy it as they like.