Here is an interesting article on what Anti-Catholicism is. I think this rings pretty much true.
Anti-Catholic themes may be loosely categorized as follows:
*]attacking Catholicism as being un-Christian or a cult (in the pejorative and not the sociological sense);
*]ridiculing or misinterpreting Catholic doctrine or practice;
*]ascribing to the Catholic Church a sinister role in an anti-Christian or anti-American conspiracy;
*]distorting or taking out of context illegal or scandalous behavior (especially sexual misconduct) by Catholic clergy or laity.
Some of the Protestant Apologists here have fit one or two of the catagories. Some Ex-Catholics here have distort our doctrines and practices. In any sense, they have no sense of trying to understand what we truly believe.
Here is the Article.