Is this really so surprising? The U.S. is a land of pluralism, and we live in a "connected" society. Information about other faiths is readily available in ways never before conceived of. Furthermore, people are quite mobile. But it's not just a phenomenon of contemporary times. Anytime people of different faiths or other ideologies live together they trade their ideas and practices back and forth. Some ideas and/or practices are assimilated others rejected. At any rate, I don't see the idea that Americans are flexible in their faith so astounding. Whether or not it's a good or bad phenomenon is worthy of discussion.
Having grown up within Catholic circles, I had not explored other faiths until I left home to join the U.S Air Force. There the various religious faiths shared facilities, like the chapels. Also, I met others, both Catholics and non-Catholics whose religious practices differed from mine. I got to know them, and they me. Some invited me to experience their religious services. Although I was not necessarily eager for this, I also felt the need to be respectful of their sincerity. When I attended, for example, Catholic Charismatic prayer meetings, it was an experience that I found interesting and attractive at some level. I had many Catholic charismatic friends and I developed a better understanding and experience of the work of the Holy Spirit. I began, as well, to read Protestant Pentecostal literature. Even their writings shed light on my own faith and beliefs.
Outside of Catholic circles I went to a Protestant revival or two. They were fun because of their liveliness and the dynamic speakers. I felt I could enjoy that, but I knew my own faith well enough not to get caught up in their theological ideas, which differed from Catholic, or their altar calls, because I harbored no doubts that I knew the Lord as my Savior long before all of these events.
One of the sergeants with whom I worked as a medical lab instructor invited me to attend the Episcopalian church service with his family. I did so, but asked him, in turn to come to a Catholic Mass. At that time the Episcopalian religious services were similar to Catholic, although I saw differences such as the way they received communion and that they permitted very young preschool children to receive. As a Catholic I did not participate in the Communion service because the Catholic theological understanding of Communion is very different. I also noticed the Lutheran's had a service that looked very much like Catholic Mass.
One of my roommates decided to become a Mormon. She asked me to go with her to her baptism. I did. I had never seen a baptism by immersion. It sort of wowed me. Catholics do that nowadays, too, as one option for getting baptized. The other thing I remember is that there were individuals who stood up and gave personal testimonies about their faith. That, too, wowed me. I was simply not used to hearing people talk that way about such personal matters. I see more of this in the Catholic faith now, for example in small faith-sharing groups.
These are just a few of my memories of those years. Had I not been in the particular situation of being in that military environment I probably would not have had those experiences. While exploring other faiths in this way I never, even for a minute, considered that I was practicing those faiths. I guess I saw myself as a spectator, just checking things out, and just responding to invitations that came my way. And, I never substituted those religious services for going to a Catholic Mass.
Now, as to the question is this trend toward actually practicing other faiths good or bad, I guess one would have to speak to those who do it. I am aware of cases where a Catholic marries a non-Catholic and the couple raises the children in both faiths. I would not be able to do that. For a Catholic it would actually be wrong to do that, because when we have our children baptized we promise to raise them in the practice of the Catholic faith.
In reading the ABC News article linked below, I especially noted the comments of Glenda Somerville who is Catholic, but who attends religious services of other denominations. She does this because she says God embraces all people and she doesn't, therefore, want to ignore other denominations. My question(s) to her would be, "If you didn't go to non-Catholic religious services, would that mean you are ignoring those people? Might there be other avenues of dialogue or working on common social projects?"
She made another comment that I found more compelling. She said that in the other services women are allowed roles that they are not allowed in the Catholic faith. They can be ministers and they can preach. Here, especially in the preaching, I think she has a good point. It is also a contentious one for some Catholic women who view the absence of female clergy in the Catholic Church as oppression of women. Although I don't hold such an extreme view, I would like to see Catholic women be allowed to preach at Mass. Yes, I'd love to see that happen.
I am not at all surprised at the findings of the Pew Study.
Pew Study Finds Americans Surprisingly Flexible in Faith and Religion - ABC News