Why were American Protestants afraid of increased catholic immigration

American Protestants were afraid of the increased catholic immigration since they felt threatened by the idea of America becoming a Catholic country.

On the one hand, Catholics believed a different Christianity than Protestants. Protestants, as opposed to the Catholic church, thought the following: Less hierarchy in church structure. The Bible and, not the sacraments, as source of revelation from God Jesus as the only necessary intercessor with God. There was an prejudice from anti-catholics that has to do with social class or status of the inmigrants. Protestants from upper classes, believed that the inmigrants were poor, therefore, they associated them with crime, danger and laziness. The fear from the American protestants created by the massive flow of catholic inmigrants, was so big that even a popular national organization, the American Protective Association, was founded to promote anti-Catholicism.