Do you suppose that they are confusing Baptists and Methodists down south? You'd not think that would happen. But still....
Possibly. My wife grew up RCC and in her particular parish, during confirmation, they were simply taught about "Protestants", and not ever any individual protestant groups. In fact one of her sisters told me just the other day that she didn't even know the NAMES of any other Protestant churches other than Methodists (because of me) and Baptists (because of a friend of hers). She said when she was a kid she thought all Protestants were Lutherans because of Martin Luther.
In her confirmation class about "Protestants" she was taught that all protestants are congregational, don't believe in sacraments, and are mostly small loosely organized groups. She was also taught that the U.S. is "mostly Catholic" which is actually far, far from the truth. While there are more Roman Catholics than any one particular Protestant denomination in the U.S., the U.S. is a very much protestant nation. The U.S. is 52% Protestant and 23% Roman Catholic, with Evangelical Protestants edging out Mainline Protestants.
From what she learned it seemed she learned (along with beliefs about OSAS, etc.) that she learned about Evangelical Protestantism, especially Calvinist theology; and was made to attribute those beliefs to ALL Protestants.
To their credit, though I have a unique experience of dating a former Catholic for 7 years and then marrying her, this year will be 4 years, most of my congregation and in fact many of my colleagues know very little about Roman Catholicism. They can probably touch the high points; the pope, no women in Ordained ministry (though they are in 'consecrated' ministry, if that's any consolation I suppose. And just like the UMC has had Pastors performing same-sex marriages in defiance of Church law, some RCC Bishops have ordained female Priests. There are also some married priests, through special permission from the Pope. One is in Kirkwood and one is 20 minutes from me in fact!). Maybe they'd know something about transubstantiation. But beyond that, many don't know much about the RCC. Or the ELCA or LCMS (or even know there's a distinction), etc. etc. Folks seem to know about their "home turf" and that's about it.