The Reasons Why the Catholic Bible is Rejected by Modern Churches
I do have one question, and that is, why don't the Protestants accept the Deutero-canonical books of the Bible, like Maccabees and such? -Robert
For the sake of people reading my answer, I'll first explain some of the terms you used. "Protestant" is the term used to describe any church that is not Catholic or Eastern Orthodox. Since the churches under this category were originally "protesting" Catholic abuses of the Faith, the word "Protestant" became popular to identify such churches. The Deutero-canonical Scriptures (also called the Apocrypha and often known as the Catholic Bible) are a set of books that the ancient Greek version of the Old Testament included as Scripture but were not included in the Hebrew Old Testament. This Greek version was the one that the apostles accepted in the New Testament whenever they quoted the Old Testament. These books include 1 and 2 Maccabees, the Book of Judith, the Book of Tobith, and about 10 other books. The early Christians inherited from the apostles the universal Tradition that these books were Scriptures that were Holy Spirit inspired, yet they were treated as less authoritative than the rest of the Bible. They were often described as introductory Scriptures, while the rest of the Bible was understood as more spiritually advanced.

The first Christians, due to the apostolic witness, unanimously made no distinction between the Deutero-canonical books and the rest of the Bible. But between AD 200-400, a minority of Christians began to doubt that these books should be considered Scriptural, due to the fact that during this time, the Jews had finally determined these books to be non-biblical. St. Jerome in the 4th-5th centuries was the most famous critic of the Apocrypha, even though from time to time he quoted it as teachings from the Holy Spirit. But after St. Jerome, the early Church could no longer accept such criticism, thanks to the weight of evidence from sacred history, Scripture, and apostolic Tradition. Nevertheless, Martin Luther in the 16th century revived the minority opinion regarding the Deutero-canonical Scriptures and he declared them to be non-biblical and not at all Holy Spirit inspired. He also declared that certain books in the New Testament were also non-biblical and not at all Holy Spirit inspired- Hebrews, Jude, James, and Revelation.
The reasons why Luther sought to erase certain doctrines from the Bible is because he believed that certain apostolic traditions (such as the ancient traditions deciding which books should go into the Bible and which books should be left out, as well as the holy traditions teaching that salvation does not come by faith alone), actually came from false human traditions. Luther did this because he was aware that certain Catholic abuses of the Faith had come from non-biblical traditions, so he sought to purify Christianity from those errors. However, Luther sometimes confused Catholic traditions with apostolic traditions, thanks to the system of Catholic education, which taught people to believe that Catholic traditions are the same as apostolic traditions. So the Apocrypha was a victim of the theological confusion prevalent in his time and place. Ironically, what the Catholics did to the Faith is precisely what Martin Luther did by rejecting the Apocrypha and other Scriptures. He decided to fuse his own traditions with apostolic traditions and declare them both to be apostolic traditions from the Holy Spirit. From then on, all the other Protestant reformers and churches, like Calvin, Wesley, the Baptists, the Presbyerians, so and many others, have considered it sensible to adopt most of Luther's traditions, like rejecting the Apocrypha and other apostolic doctrines, believing by this that they are purifying the Faith. So instead of believing and practicing what the early Christians accepted, both the Catholics and the Protestants have innocently (though not always innocently) made up their own traditions and Bible interpretations and then convinced their followers to believe that these were all apostolic traditions.
I hope this totally explains your question. Let me know if you'd like more elaboration. -Gaius

Follow-up Question:
I found out from these Orthodox ladies that the original 1611 King James Bible had the Deuturo-canonical books in it. You might want to look in to that, considering all the Protestants that swear by that version. -Robert

Follow-up Answer:
That doesn't surprise me. I didn't want to make my answer too long with talking about the Apocrypha's Protestant history. After Martin Luther rejected the Deutero-canonical books and 4 books of the New Testament (Hebrews, James, Jude, Revelation), not all Protestants initially agreed. Though some Protestant churches did throw out the Apocrypha and these 4 New Testament books from the Bible for about 100 years, some bibles of the Methodists, the later Lutherans, and many other Protestant churches continued to keep all these books in the Bible, even the Apocrypha. But Luther's teachings rejecting the Deutero-canonical books became more and more popular over the centuries. By the 1900's it became rare to find a Protestant Bible including the Apocrypha, though the 4 New Testament books which did not agree with Luther's new gospel have remained in all Protestant bibles. Keep up the good research! -Gaius