What ethnicity are we talking here? Also an eleven sibling family is obviously going to be quite a bit more traditional on this than some kids from a mixed marriage really casually Catholic family...
Here's the big issue I see with this line of thinking, if being Catholic is something you don't choose, and being an evangelical is something you do choose, then what is a Catholic who converts to evangelicalism? I mean you have 1/3 of people raised Catholic today who don't identify as such anymore (about half of whon have converted to something else, half of who simply identify as "none".) That's hardly a negligible number. My mom had no problem getting married in a Lutheran church and didn't raise her kids Catholic. It's kind of absurd to still label someone like that Catholic, especially if they don't.
I mean if people who are barely practicing want to still call themselves Catholic I guess they can (even though I have literally never met such a person in real life) and I understand the point that there is a difference between actually converting to something else and simply lapsing into non-practice, but can't anyone see the issue with still labeling someone a Catholic if they specifically don't want to be? And this applies to 1 in 3 people raised Catholic and 10% of the population, not some fringe number. Not every person raised Catholic is similar to how patrick described, or part of an ethnicity intrinsically tied to Catholicism, or so tied up in that ethnic identity they can't drop the religious one.
A few things seem strange to me about your thinking. First, you seem to think that a family with 11 siblings must be antithetical to the concept of mixed marriages. This is demonstrably false. In fact, each of my four grandparents were born in different countries. Two of them migrated here with their families as children, and two came independently as adults. Each couple met here. Those eleven siblings on my father's side were in fact the product of a mixed marriage, and the same things is true on my mother's side, although in both cases the mixings were between various tribes of white people. And not all were catholic. On one side it was a fairly unobservant Roman Catholic marrying a fairly unobservant Jew, and on the other side it was a sort-of practicing Roman Catholic marrying a fairly unobservant Eastern Orthodox Catholic. In both cases, the Roman Catholic identity seemed to have been dominant, and that's how the children were raised. Moreover, among those 11 siblings in my father's side, only six married within the Americanized ethnicity group of either parent. The other five married into some other tribe of white people. Among
their children, the grandchildren of my grandparents, the tribal mixing became even more exotic and distant. As a result, I have first cousins who are black, Ojibwa (also called Chippewa in your part of the country), East Asian, hispanic, and Navajo. Just a fine point, but I thought it should be made.
Secondly, Catholics who convert to Protestant are Protestant. Anyone will tell you that. I know folks who fit this description. This doesn't contradict my original point. I said being Catholic is something you are generally born with, so you don't choose it. (You can choose it, of course. Jews and Prots who marry Catholics sometimes do this, but it's a very formal process, taking a long time and lots of emotional energy and not so common I think. It's not like becoming, say, a Muslim, where all you have to do is say something and really mean it.) But syllogism doesn't mean that the reverse is true. That is, a Catholic can choose to become a Protestant (or a Jew. I know of one case in which a Catholic man maried a somewhat observant Jewish woman and converted. You think becoming a catholic is a hassle? Try becoming a Jew. He said that they actually drew blood. I'm assuming that he was serious.) That convert makes a postitive action to revert away from Catholicism. This would be the case in conversion to another religion, in the denunciation of Catholicism, and probably in many cases of forced excommunication by the church. (Although I expect that some excommunicants will still consider themselves Catholic.) In all cases of voluntary separation, your point is valid. But you should not conflate voluntary, positive separation with a simple lack of observation, or a simple agnosticism by default. The statistics back me up on this. As I mentioned, in Spain, for example, 75% of the people self-identify as Catholic while at the same time 59% of Spaniards claim never to attend religious services. Similar statistics hold for France. Pick any society you want. This idea that someone will self-identify as a Catholic while simultaneously answer "yes" to a pollster's question that he/she is skeptical about the existence of God and/or non-practicing of any religion is NOT limited to the Eastern United States.
Thirdly, I'm not trying to oversimplify. Hockeydude's point about regional differences isn't without merit. You can look at states where Catholics are a plurality among Christian denominations: CA (31%), TX (29%), NJ (37%), etc., and you will find some trend. Mostly it has to do with the fact that in the Southwest, those Catholics are often Hispanic. More likely to have an Our Lady of Guadelupe candle on the mantle or a flaming crucifix tattooed on their back. For them, just as with the New Jersey Catholics, the Catholicism is part of their ethnic identity, but they are more likely to actually practice the religion, whereas the New Jersey Catholics see Catholicism just as more of their (Irish-American or Italian-American or Polish-American) identity. Still, the phenomenon among the non-hispanic Catholics in all these regions is the same with regards to seeing Catholicism as part of who they are, even if they don't practice. Even among many Hispanics, this will be the case.
