My question is this - how can Protestants get so riled up about Catholic doctrine when there are thousands of different denominations who are under the umbrella of the word ‘Protestant’. Do they not care about the doctrinal differences among themselves being much more egregious? Jut my humble opinion.
Because much of the bible is a warning about the gall of bitterness and mystery of iniquity of the Catholic Church. It's what the founding fathers spoke of, when they spoke of the papists, and the papist's opposition to liberty.