I really agree with your sentiments, that first paragraph is a great quote. I grew quite an adverse to MongoDB after researching it. While I never found this specific caveat, I found other very worrying decisions.

> reliable storage engine

By "reliable" I assume you mean "consistent?" While MongoDB claims that it's CP (which it's not, as per the article) there's nothing wrong with inconsistent databases (AP, e.g. CouchDB). Mathematically there is no reason for MongoDB to behave like this. It's fundamentally broken; it's neither AP nor CP.