Not surprising. Protestants pretty much just have the Bible.
Catholics believe they have the sacramental life, the Church, Holy Tradition, etc. in addition to scripture.
I’m a protestant convert to the Catholic Church. The very idea of “church” is quite different.
I should add an important point: the Communion of Saints. This too was left behind in the Protestant revolution.
When you remove this along with the Apostolic Church, the Sacraments.. you’re pretty much left with scripture as the sole remaining piece.
I realize most protestants make a virtue of this and are fine with it. My point is if it’s all that’s left, then it’s no surprise in the disproportion noted in your post.
I still watch the ABC crawl in Times Square with total bafflement if I haven't already read the news elsewhere. That's even worse, because you don't have a story to read to take you out of double-digit-IQ land.
Protestants receive the sacraments much less frequently than Catholics, and rarely, if ever attend Mass. Protestants are more likely to use terms like “saved”, “slain in the spirit” and “born again” than Catholics. Catholics are much more likely to own a RSV or Douey Rheims bible and Protestants are more likely to own an NIV.