It is often a wonder why the three major streams of Christianity differ in the contents of their Old Testaments. Between the Roman Catholic, Eastern Orthodox and Protestants, it is the Protestants that have the smallest number of books of the Old Testament(OT). The differences all stem from the way theses streams treat the OT books found in the Septuagint - the Greek translation of the Hebrew Bible. At the end of the Book of Malachi, a few more books were appended like Tobith, Judith, Baruch etc. in the Septuagint.
The word apocrypha stands for the Greek word "hidden" which was used by the church father Jerome to describe these books - meaning of questionable inspiration. Another church father Augustine considered these books to be inspired. Which church father do you believe? It is a myth to think that the church fathers, to which RC apologists are proud to appeal to as their source of doctrine and practice, were always in agreement. Well did the Reformers say that these church fathers contradicted each other. At anyrate, the RC called these books euphemistically "deuterocanonical", i.e. to mean accepted later as inspired.
Why then did the Protestants not include these books in their OT? Because the Jews did not consider them inspired either. I think this is a sound procedure, because the OT is the book of the Jews from which the Lord comes from and if there is a people who would know their OT, it would be the Jews. Besides this, all along there were early Christians who did not consider these apocryphal books as divine either, whereas the regular canonical books of the OT were accepted without any disputation as inspired. Therefore, it is a safer policy to consider these books as not inspired, and not to take one's doctrine and practice from them.