Blessed Virgin Mary 

You need to understand that the article to the BLESSED Virgin Mary is used in Roman Catholic articles.

While the VIRGIN MARY relates to Protestant/Secular views on the Virgin Mary.

The title of the Blessed Virgin Mary is a valid honorific title, just as SAINT MARY is permitted by Wikipedia.

The point is, if its a Catholic article, its a Catholic title of the BLESSED Virgin Mary.

See the difference. Visit both pages.