Why is the Catholic Church the subject of such hatred from other Christians? I've noticed that except for the hard-core fundamentalists who suspect (and shun) anyone outside their own congregations, most Christians will give other denominations the benefit of the doubt, even if they know nothing about what those other denominations teach.
I as an evangelical Presbyterian have never heard other Presbyterians speak with suspicion or hatred of Methodists or Lutherans or Congregationalists. Even when there is a clear difference in basic tenets of faith, such as exists between Presbyterians (or Lutherans or Episcopalians) and Baptists, I've never heard people of one Protestant denomination say that people in the other denominations aren't saved, or that they're involved with the Whore of Babylon (or similar hateful things).
And people who are long-time members of one denomination are just as unlikely to know anything about the others as they are to know anything about the Catholic Church. Yet they assume that the tenets of faith in other Protestant denominations are basically the same as their own, but have no compunction about strongly asserting that the Catholic Church is in grave error or heresy, even though they've never bothered to learn anything about any denomination outside their own.
Why the fear - so strong that a practicing Christian often isn't willing to even engage in a conversation where Catholicism is defended, even mildly? If that's not a sign of Satan trying to prevent God's people from hearing the truth, I don't know what is! I don't see any other explanation that fits the excessive reactions that people have to even the mention of Catholicism.
Another former Presbyterian (now Catholic) woman wrote:
In spiritual terms, the hatred for the Catholic Church is inevitable since hell is attempting to prevail against it. Just as Jesus' physical body was spit upon, scourged, beaten and pierced, so too the Body of Christ, his bride, his Catholic Church, is maltreated. Yet he himself has told us that the gates of hell will not prevail against it, and we who are Catholics believe him.
And we Protestants who have become Catholics have paid a great price to not only believe him with our minds and hearts, but with our bodies. All of us have lost friends, many of us have lost family. Yet all of us have gained glorious peace, joy, hope and love to have joined our bodies to the One, Holy, Catholic and Apostolic Church established by our One Lord and Savior, Jesus Christ.
For one thing, the hatred is prevalent because the Catholic Church is a huge target, by sheer size and influence. It's like one of those great big red barns in the countryside that we've all seen, whereas Protestant denominations are more like moving ducks at a carnival: there are far too many to get "mad" at any one of them, and they are moving targets. Even if one takes a few shots, one is likely to miss. It is the very mountain-like "immovability" of Catholic doctrine that is oddly despised by so many.
Secondly, the Catholic Church is the victim of more misrepresentation than any other religious belief, in my opinion. Why? Well, I suspect that it is equal parts ignorance and hostility that is borne of ignorance. So we often see criticisms "of" Catholicism that really aren't at all, because we don't believe what it is falsely claimed that we believe. Rather, it's a straw man, or warring against windmills, like Don Quixote.
Thirdly, we teach a very strict morality (because we have preserved apostolic Christian morality). Folks don't like that and so in order to counter it they run down the Catholic Church, so they can feel more comfortable in rejecting it. Evangelicals get some of this, too, but Catholics more so because we are stricter on divorce, contraception, masturbation, etc., and even things like compulsory church attendance every Sunday and dietary requirements during Lent.
What G.K. Chesterton observed about Christianity applies especially to Catholic Christianity: "Christianity has not been tried and found wanting. It has been found difficult and left untried."