Why is it that Catholics and Orthodox have a deeper knowledge of church history than Protestants?

For example, my mother is a Protestant yet she does not know anything about how Protestantism came from the Roman Catholic church. She constantly tells me she does not want to "mess up her mind". Why does she want to be blind to the facts that the Catholic and the Orthodox are EQUALLY as Christian as her United Methodists. It's just so mest up when she says that that Catholics add books to their Bible. When in actuallity, Protestants have TAKEN AWAY from the Bible. The Bible originally included the Apocrypha. The Roman Catholic church and the Eastern Orthodox church came BEFORE any Protestant church. It just pisses me off that some Protestants completely reject Catholicism and Orthodoxy as not Christian. When will they stop this? I'm sorry but I don't believe Christianity is exclusive to Protestants only. I just know that Christianity began with the church in Acts and came to be known later as the Roman Catholic church and Eastern Orthodox church.