I hope this is the right place for this question.
It seems to be a uniquely American issue this but why do some "Christians" not label Catholics also as Christians but make some distinction and label them as Catholics. After all, all the denominations profess to be followers of Christ - hence the "Christian" label.
I've even seen comments to the effect that "they are not Christians", they're Catholics.
I know there is a prohibition in these threads about "you're not a real Christian" but this isn't about that - it's just about the labeling convention. Other countries don't seem to segregate the two to the same extent.
I'd offer there are a few ingredients in that recipe.
1) Historical antagonism between Roman Catholics and Protestants. Since the Reformation hostility has existed on both sides, Protestants of every stripe were labeled as heretics by Rome; whereas Protestant groups regarded Rome as having fallen astray. This in not a few instances actually erupted into actual violence, including wars between nations--the Wars of Religion, political rivalries that would continue to play out in the international stage. Protestant Dutch and Catholic Portuguese fighting and competing in Asia, one of the reasons that led to Christianity being illegal in Japan was that Dutch traders whose religious-political-econcomic rivalry with the Portuguese had the Dutch claiming the Jesuit missionaries were merely a vanguard of conquest--leading to the laws making Christianity illegal and Japan closing itself off from contact with most of the rest of the world for another couple hundred years. This animosity continued in the New World, here in the United States, and in the 19th century there existed a very powerful anti-Catholic sentiment in the country that often led to prejudice and discrimination against immigrants (in particular Irish and Italian immigrants).
While the Vatican II council officially and formally decreed that Protestants were not heretics but merely "separated brethren" and while many Protestants have likewise either formally or informally rejected anti-Catholic rhetoric, there are many hold-outs of anti-Catholic sentiment. Carry-over from a former era where Catholicism was to be feared, despised, and held as suspicious; as a pronounced example of this just consider the religious tracts produced by Jack Chick/Chick Publications.
2) A very strong Evangelical culture that comprehends itself as "just Christian" and anything else as superfluous or else outside of Christianity. As someone who was raised in an Evangelical/Pentecostal environment a pronounced way of thinking that seeped through was an idea that we were "just Christians". Ours was what was normative, anything else was suspicious, and we were "just Christians" as opposed to Catholics, Lutherans, Episcopalians, Methodists, etc.
3) A general ignorance of what Christianity looks like outside of the very tiny microcosm of Evangelicalism. A common trend is the significant lack of understanding between various Christian groups; and generally the more culturally entrenched they are the more likely there is to not ever have to encounter persons of very different beliefs and positions. This isn't unique to Evangelicalism or to America, but in the case of America Evangelicalism is a very entrenched into the American psyche. The only knowledge one may have of other Christians, at best, may only come from what you hear people at your church say, and there's a distinct possibility that what you're hearing is just plain rubbish. Going back to my own experiences growing up, I had been taught that Catholics depict Jesus hanging on the cross (a crucifix as opposed to an empty or plain cross) because they don't believe He was raised from the dead but was still dead and on the cross somewhere. This is so obviously nonsense, but I've since heard it many times while participating on online discussions. So there remains simply a sheer and profound ignorance, and unless one is legitimately motivated to learn and move outside of their comfort zone they may never be properly educated on such simple things.
I'd say all three, or combinations of these three, are readily available for some to thus utilize in order to, wrongly and ignorantly, claim that Christians and Catholics are somehow distinct or different.
-CryptoLutheran