My experience is that it's hard to generalize. There are Catholics, including many who post here, who obviously have a deep attachment to the Church. Fine. But sometimes they indicate an attitude of condescension toward Protestants, as though Protestants were something 'less Christian' because of differences.
Among Protestants you will find some who still harbor a striong prejudice against Catholicism. They regard it as a pagan cult teaching superstitions from earlier times. Fundamentalist Protestants are most likely to have such a bias.
Good news. The recent Pew poll indicated that only 16% of American Catholics and only 12% of mainline Protestants (Methodists, Presbyterians, Episcopalians, etc) subscribe to the notion that they have the only true religion. Not as encouraging: something like 45% of evangelical Protestants and about the same percentage of Black Protestants believe they possess the full truth essential to getting into heaven.
What surprised me is that so few Catholics seem to accept the idea that they belong to the only one, true apostolic Church. Unfortunately, some Catholic media (e. g., EWTN) seem to promote a Catholic triumphalism that gives non-Catholics the impressive that Catholicism is intolerant. I've heard that telecasts like "Journey Home" grate on Protestants who would like a warm ecumenical relationship among Christians. If one group says they have the only authentic Christianity, the only valid communion, the only true Church, etc - as Benedict XI stated last summer - warm ecumenism is difficult to achieve.
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